There are two kinds of libraries: archives, which try to keep everything relevant for ever, and circulating libraries, which try to be useful to the public.<p>Municipal libraries are circulating libraries, so if they spend $80 on TAOCP vol. 1 and it&#x27;s borrowed once, they basically wasted $80.  They should have spent the $80 on something else that people would borrow multiple times, and the person who wanted TAOCP could have gotten it via inter-library loan (probably from some university library).<p>And I think online databases and Wikipedia are busily killing off physical reference books.