I have 2 of the 7 books of the X Window Programming Reference in that role. Apart from K&R, there are very few programming books which are worthwhile; up to about 10 years ago the ORA series were worthwhile, but nowadays especially with StackExchange it's just far better to get the one fragment of information you need in a handy searchable pasteable internet format. (Non-programming book recs: recently The Man Who Stole Portugal (non-fiction, surprisingly relevant to crypto) and The Time Of Gifts (biography, extravagantly written, requires checking wikipedia every 5 dozen words unless you have a really excellent knowledge of European history)
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