For incoming/current graduate students
Managing your Mental Health during your PhD by Zoe Eyres - If you read one book before/during grad school (lol), let it be this one. The book has also been made available as a Spotify podcast, rather than an audiobook, so listening is free and unlimited! I believe it is also available as an ebook through most university libraries.
A Field Guide to Grad School: Uncovering the Hidden Curriculum by Jessica McCrory Calarco
Grad School Essentials: A Crash Course in Scholarly Skills by Zachary Stone