These are the books that have helped me grow most as a developer. I highly recommend them all. Please note that the links are affiliate links and a small portion of any purchases you make will go towards the costs of maintaining this site.
Practical Vim by Drew Neil
Practical Vim is a must have book for anyone who wants to be efficient while editing text. While it's a book about Vim, it will challenge you to use your editor more efficiently and powerfully no matter what you use (and maybe convince you to switch to Vim). Highly recommended for anyone who deals with code or text for a living.
Tmux: Mouse Free Productivity By Brian Hogan
Tmux is a terminal multiplexer, a program that allows you to split and organize your terminal windows. With an unfriendly project page and a dearth of great tutorials out there, it can be a bit difficult to get started with. Tmux: Mouse Free Productivity is a short (88 pages) little guide to using Tmux effectively. It helped me get up and running with what is now an indispensable tool in my workflow.
The Pragmatic Programmer by Andrew Hunt and David Thomas
This is a classic in the programming field, easily the most well known book on this list. But it also is an indispensible explanation of the process of making great software. There's not a lot of code in this book, and thats a feature, not a bug. This is a book about the techniques of building a software project, not the nitty gritty details. As such, it's relevance has lasted a lot longer than instructional books which have come and gone.