A county's library stock fell by nearly half a million books in a decade, new figures reveal.
The number of books in Essex declined from 1.76 million to 1.29 million between 2007-08 and 2017-18 - a drop of 27%.
Save Our Libraries Essex, which obtained the statistics, said Essex County Council was "setting the library service up to fail".
The council said the book stock was updated in response to demand.
Over the period, Colchester Library saw the number of books available on its shelves fall by 64,444, while Chelmsford's stock dropped by 69,481, a Freedom of Information Act request showed.
The number of books in Harlow Library fell from 74,716 to 33,053 volumes.
The council in July reversed a decision to close 25 of 74 libraries - after opposition from campaigners - but said it wanted volunteers to run some smaller branches.
Andy Abbott, of campaign group Save Our Libraries, said he was concerned fewer books would lead to fewer library users.
"If you were running a bookshop and reduced the stock you would expect to lose customers. Essex County Council is setting the library service up to fail so they can then cut libraries," he said.
"They must not continue cutting the numbers of books and they should put the proper investment in to buying books."
Essex County Council said the books removed were either not being borrowed or too damaged to lend.
It added that an extra £130,000 was spent last year on books in Essex.
The Conservative-run council made a U-turn last year after a major campaign against the plans was backed by celebrities including comedian and writer David Walliams, poet Michael Rosen and author AL Kennedy.