I rely mostly on hypertext for referencing, mostly through Dash for macOS and man pages. Books that I still occasionally reference:

- Speech and Language Processing, Jurafsky & Martin

- K&R

- Sedgewick & Wayne, but more for teaching than anything else.

In a previous life:

- The C++ Standard Library, Nicolai Josuttis,

- C++ GUI Programming with Qt 4, Jasmin Blanchette and Mark Summerfield

- The C++ Programming Language, Bjarne Stroustrup

- Effective Java, Joshua Bloch

- Scott Meyers' Effective C++ books.