I'm a big fan of O'Reilly technical books. I'm currently reading Designing Data Intensive Applications which should be required reading for almost all engineers. I've previously read Internet Core Protocols to replace the networking class I didn't take in college, and a few books on embedded programming.
In a previous life as a Java engineer, I had read Joshua Bloch's Effective Java, which at the time was considered to the the holy scriptures of Java development. Although I've been programming in mostly in Python for two years professionally, I realized I hadn't read any book on Python development that was similar. In searching for books to fill this void I came across Fluent Python and Python Cookbook, the latter of which also looked like it would be helpful for solving leetcoding problems. Both of these were published by O'Reilly, and while I mostly prefer good old dead trees, I wasn't sure I wanted to have two more 700+ page books on my shelf, so I thought about a digital subscription
An O'Reilly digital subscription costs $50/month or $500/year for an individual...but an ACM membership costs $200/year and comes with a large digital library AND an O'Reilly memberhip! Hot tip for other engineers out there, just buy an ACM membership with the digital library addon!