I've been toying with the idea of writing a Drupal book for a few years now but with Drupal 10 on the Horizon, I decided it was finally time. So:
TADAH!!! I present: Drupal at your fingertips - a Modern Drupal developers' quick reference guide.
I hope folks enjoy my effort. I really love Drupal, the whole idea of the project, as well as the open source movement. It is such an elegant way to create amazing software.