I guess my buckets are different. I have CPU books (eg. Programming the Z80), language books (eg. K&R), sysadmin books (a bunch of old O'Reilly), operating sys

I guess my buckets are different. I have CPU books (eg. Programming the Z80), language books (eg. K&R), sysadmin books (a bunch of old O'Reilly), operating systems (VMS, Multics, Unix, Windows, BeOS, QNX, etc), a heap of GUI toolkit books (X11, Qt, Tk). History and culture (Soul of a New Machine, Fire in the Valley, etc), craft books (Hackers Delight, Knuth, GoF, etc). A few manuals (eg. NeXTstep), some hardware (USB, Ethernet, LTE), networks, etc. These days I mostly buy language and history/culture books.