At the moment, my favorite is rather unusual:
I can't remember the title, but the author was der Herr Doktor Ernst Vogel - published in Berlin in 1904. There's a lot of good basic information in books written in a time when differences between various lens formulas and constructions were important for a photographer to know!
The good doctor also gives instructions in making your own plates - gelatin or collodion dry plate, what dyes to add to improve sensitivity/ colour sensitivity and so on.
The only commecial developer at the time was Rodinal from "Aktiengesellschaft für Anilin-Fabrikation", later known as AGFA. So there are lots of developer recipes as well.
The printing section contains everything one could wish for - "alternative" metods weren't alternative a century ago!

This will probably change next week, when I begin looking at some other books. Favorites seem to be dependent on mood and/or time of year: It's almost as bad as asking me about my favorite wine.