Simple RAW for 5e 4: Smackdown v. RAW

[E’Tallitnics]

Q411

Does this mean that if I find a spellbook with cantrips in it, they are useless to me? There's no use to which they can be put?

Should cantrips even appear in spellbooks?

(Disclaimer: my DM has given us an enemy spellbook that does have cantrips in it, so it's not just theoretical for me.)

R411: RAW:

• Cantrips should not appear in spellbooks. Only spells of 1st level or higher may be added. (PH-p.114 [green sidebar])
• You can create a spell scroll of a cantrip, but it must be prepared or from known spells. (XGtE-p.133)

Since your DM is the final arbiter of the rules please them about their reasoning for giving you a spellbook with cantrips. They may be unaware of the RAW, or are aware and have something else in mind.