Some of the feats in D&D 5e are seemingly less useful or otherwise not always as reliable relative to the other feats, although they are very flavorful. Keen Mind is one such feat, granting your character a 30-day eidetic memory, master navigator, and time keeper.

However, there can be workarounds for the last two benefits (benevolent DM, hand waving, finding NPCs who know the area, etc), and the first benefit does not seem to have an everyday usefulness to shortlist this feat for a wizard -- not over War Caster, Resilient(Con), Alert, or Tough, for example.

At best, people seem to think it's just a way to make the DM rehash their old hints if you missed them the first time.

Here is the text for Keen Mind:

Keen Mind

You have a mind that can track time, direction, and detail with uncanny precision. You gain the following benefits.

  • Increase your Intelligence score by 1, to a maximum of 20.
  • You always know which way is north.
  • You always know the number of hours left before the next sunrise or sunset.
  • You can accurately recall anything you have seen or heard within the past month.

If you're a wizard, you will be reading your spellbook everyday. It is within the bounds of the feat to say you recall absolutely every glyph, symbol, and diagram of your spellbook, down to the ink stains and page number of each word of each spell.

One cool way to make use of Keen Mind is to make the spellbook obsolete -- within the DM's approvals/restrictions.

Here are things a wizard can do because of their spellbook:

  • They can change their prepared spells after a long rest
  • They can scribe new spells upon gaining Wizard levels
  • They can cast rituals without expending spell slots
  • They can use Arcane Recovery
  • They can gain Spell Mastery or Signature Spell if they have the spellbook upon leveling up

If the wizard has the spellbook engraved in their mind, which of these things can the wizard still do, and which can they no longer do, if that same wizard did not have a spellbook at hand for some reason?

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    \$\begingroup\$ Note that your premise has an error, as you cannot gain the other benefits of Keen Mind easily by in-game means: there is no compass in the 5e equipment lists (personal compasses are a post-medieval technology); hour glasses don't work that way (they are timers not clocks); and making and using a map means you lose your Passive Perception score (PHB, p. 183). Keen Mind has a lot of benefits in games where the GM is being impartial about information access and not giving it away for free. \$\endgroup\$ Mar 16, 2016 at 18:01
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    \$\begingroup\$ @SevenSidedDie Good catch with the compass and map. I mentioned hourglasses because you could still technically track time with it, if you had a large/numerous enough hourglass that causes sand to fall slowly enough (essentially a 12-hour timer). It would not be convenient. Still, even then, one would probably still pass Keen Mind up for the other feats I mentioned for combat effectiveness. \$\endgroup\$
    – user27327
    Mar 16, 2016 at 18:52
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    \$\begingroup\$ Depends on whether the Combat pillar is being promoted over the Exporation and Roleplay pillars or not. But regardless: the question asked is plenty interesting and useful. :) \$\endgroup\$ Mar 16, 2016 at 19:17
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    \$\begingroup\$ @SevenSidedDie Conner's A People's History of Science (2005) gives an excellent chapter or two on the (not-trivial) development of proper clocks that can be used at sea, and different navigational technologies where there is no compass. This material is ripe for those doing world-building and wanting to understand society/technology relationships, in addition to being a fabulous history bok in general. :) \$\endgroup\$
    – Lexible
    Mar 16, 2016 at 19:48
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    \$\begingroup\$ @markovchain 2 things: 1) you can also create a copy of your spellbook at a reduced cost (1 hour & 10 gold per spell level to scribe a spell vs. 2 hours & 50 gold per spell level); 2) assuming that your wizard has no spell book with them at the end of the month they lose any spells stored in their head aside from prepared ones \$\endgroup\$ Mar 17, 2016 at 0:41

5 Answers 5


Things you can do, by the book: Everything you listed except scribe a new spell.

Source: PHB pg. 114

That actually requires you to write down the spell, and has a material cost associated with it that is usually associated with special inks and gems. Yes, you can recall it from memory and write it into your book, upon which you would have it memorized for a month. However the spell itself may require a specific rune written in a specific ink. Knowing that, and having written it down that way are two different things. Obviously this applies to material component cost spells only.

Since the Wizard can already replace a destroyed spell book with the spells he has prepared for the day, it's reasonable to extrapolate that with photographic memory (as this feat entails) you could replace the entire book. After all, the spells don't disappear from your mind when you cast them, so this feat should serve as a good safeguard against losing your spellbook.

Of note: You're going to want to review your book monthly and update it with new spells in order to continuously preserve this.

Of secondary note: I would even allow a Wizard with this feat who passed a successful Arcana check to experiment with and replicate a spell cast by somebody he was watching. Personal DC levels would be, DC +5 per component needed (Verbal, Somatic and Material), and double the result if the Wizard isn't proficient in Arcana. But that's a house rule thing because this is a clever use of a versatile feat that effectively duplicates the spell book.

But bottom line is: Nothing under Wizard or the Spell Book sections in the PHB prevent you from recalling everything in your book from memory. The pertinent line is here:

Preparing a new list of wizard spells requires time spent studying your spellbook and memorizing the incantations and gestures you must make to cast the spell: at least 1 minute per spell level for each spell on your list.

Since Keen Mind already ensures you have the spells memorized, there`s no reason you would need to open the book in order to review them.

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    \$\begingroup\$ Would Keen Mind result in the wizard having all spells prepared, having memorized all the incantations and gestures? Would it reduce, or eliminate, the time necessary to prepare spells? \$\endgroup\$
    – Robbie
    Jul 9, 2017 at 23:44
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    \$\begingroup\$ It doesn't say it does, so I would say no. Even though they would have them all memorized, the specific spellcasting rule limits you to how many you can prepare. \$\endgroup\$ Jul 9, 2017 at 23:53
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    \$\begingroup\$ @Robbie the way I see it, the difference between "having memorized all the incantations and gestures" and having a spell prepared is like the difference between having memorized the script of a play and being ready to actually perform in it. Even if you have memorized every last word of dialogue, every movement, and every piece of scenery, you still need to practice before you perform. \$\endgroup\$ Apr 3, 2018 at 1:01
  • \$\begingroup\$ Would also add the first bullet regarding prepared spells, RAI: twitter.com/JeremyECrawford/status/664882667628855296 \$\endgroup\$
    – Blaise
    Jan 30, 2019 at 17:27

TL;DR: Keen Memory can't replace the magic on the spellbook.

Disclaimer: This answer is based on the premise that there is something inherently magical about the spellbook or the ritual of preparing spells. GM should rule about it and, if it fits with how magic is handled in your campaign, everything is possible.

The spellbook is more than just a book with your spells written on it. The book itself doesn't have to be magical, but the ink with which you write spells may be (10 gp per spell level is a lot for normal ink) and it takes a lot of time to write them (1 hour per spell level). This indicates that there is more than words on it.

Transcribing spells isn't a copy/paste process, it's a ritual that embeds the magic into the book, and memorizing spells isn't just remembering the motions, it's engraving the magic on the wizard's mind.

Even a wizard with the worst memory could remember how to cast magic missiles after casting it every day for 30 years, but still needs the magic in the spellbook to burn the spell on their mind, the same way they can project the spells burnt in their mind into a different spellbook.

Asuming now that there is something other than memory that is needed to prepare spells, the feat won't be able to substitute it. If not, then you should only need to refresh the spells once each month.

  • \$\begingroup\$ But if the connection to spells in the spellbook is magical, then why do you prepare spells by "memorizing" the spells within? PHB 114. The inset "Your Spellbook" on the same page reiterates the mechanical barrier to casting the spells and makes no mention of any magical communion implicit with the spellbook, other than your spell caster requiring the appropriate spell slots to manage the spell. Even then, this condition doesn't seem to necessarily imply a magical property of the spellbook itself, since the same condition exists for casting the prepared spells even if the book is destroyed. \$\endgroup\$
    – Blaise
    Jan 30, 2019 at 17:04


You asked what if a Keen Mind doesn't have a spellbook. By the book, the Keen Mind feat doesn't mitigate not having a spellbook, and so the Keen Mind can't do any of the items on your list.

Is Keen Mind mechanically useless?

You imply that Keen Mind is mechanically useless. Certainly in a particular situation a particular feat could be mechanically useless, but that does not necessarily apply across the board. The points listed in Keen Mind could be quite valuable. For instance, it would make it nearly impossible to get lost underground. In some campaigns that would be a serious advantage.

Does Keen Mind replace the spellbook?

You say it is within the bounds of the feat that Keen Mind could replace a physical spellbook. It is not within bounds of a by-the-rules reading of Keen Mind, because at a minimum:

  • There is a mystical component to memorizing spells, that Keen Mind does not address at all
  • Spellbooks require special ink, which says that there is something about the spellbook that is more than just the information
  • There could be more to a spellbook than spells you've memorized in the last month
  • Transcribing a spell from a spell scroll destroys the spell on the spell scroll, which implies there is something beyond memorizable information within the spell

Is a Spellbook Merely Paper and Ink?

A spellbook is not merely paper and ink, or merely rote memorization. It is somehow integral with how wizards access the source of magic. While not spelled out in so many words, it is implied by the rules:

  • Other classes access the same spells without a spellbook
  • Spell slots are recovered with Arcane Recovery, implying that use somehow removes the spell from the wizard's mind
  • The ink is "fine" in some way, implying that somehow the quality of the ink is important

All of this implies that there is something important about the process of the spellbook beyond mere memorization.

What you're suggesting is an interesting homerule

It's a cool idea. Another way to get there might be a completely homebrewed feat called, for instance, Spellbook of the Mind, which grants the abilities you're discussing. That might be really cool. Might need to cost 2 attribute points, too, since it does away with a class limitation.

  • \$\begingroup\$ I believe there are a number of inaccuracies in this answer. There's no indication that preparing spells is inherently mystical: "Preparing a new list of wizard Spells requires time spent studying your Spellbook and memorizing the incantations and gestures you must make to cast the spell". There's no indication that the inks are magical, simply incredibly high quality because you're making incredibly detailed notes with it: "The cost represents material Components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it." \$\endgroup\$
    – Samthere
    Jun 2, 2017 at 9:25
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    \$\begingroup\$ Expending a scroll as part of transcribing it is part of "reproducing the basic form of the spell", and part of the aforementioned "experimenting with the spell to master it". Scrolls are inherently magical and contain the power and materials to cast the spell. Arcane Recovery isn't relevant; you don't expend or forget prepared spells when you cast them, just spell slots. Spell slots are an abstract representation of your magical power and your physical and mental capacity to exert yourself magically. \$\endgroup\$
    – Samthere
    Jun 2, 2017 at 9:35

Preparing and casting spells (PHB p.114):

"Preparing a new list of wizard spells requires time spent studying your spellbook and memorizing the incantations and gestures you must make to cast the spell: at least 1 minute per spell level for each spell on your list."

Thus, RAW, the answer is NO, the Keen Mind feat cannot replace a Wizard's spellbook as the rule for preparation states that it takes study and memorisation. A wizard has to actively study their book to prepare spells, it is not merely an act or expression of memory and even memorising their book start to finish does not allow for the Wizard to "study it". The class feature that Wizards gain 2 additional spells in their spell book is thematically predicated on this study.


You can accurately recall anything you have seen or heard within the last month. RAW I don't see this including anything you have read in the last month. So if you had seen a page of text or book you could recall the page structure of the text and general content but not a word for word transcript of what you had read

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    \$\begingroup\$ Unless you're reading Braille, reading something requires seeing it. \$\endgroup\$ Jul 4, 2019 at 14:39

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