It has been a long long time since I bought a chess book, let alone opened one I already had. I now regret giving most of them away for the last charity book sale. But I kept one I simply cannot bring myself to part from: Horowitz' 1964 edition of Chess Openings. I remember pouring through what seemed like thousands of lines and still not really covering even half the conventional openings. I still find it interesting and I've got so many little margin notes and so forth I got to keep it, even if it probably is way out of date and so much has happened since.
And it is like 789 pages and was $8.95 --
If there is a single, favorite, well-thumbed chess book you folks hang onto for whatever reason, tell me which book and why you still have it? I know, I know, some of you will make some very bad jokes, but pls try to save us some time here and just answer the question.