A pioneering survey of library and reading preferences of prisoners in the oldest Slovak male prison in the town Leopoldov was performed and historical details are also mentioned. The library contains more than 7000 books and more than half of the regular readers (>10 books/year) among prisoners appreciate the library's richness and genre richness. The gratifying finding was that 70% of respondents perceive books as a source of information and a form of self-education. Interestingly, the textbook of English language for self-education was 6th the most borrowed book in the Leopoldov Prison and this or other education books were among the ten most borrowed books in other prisons. Data on the library richness and use by inmates in 14 Slovak prisons were collected and showed a library size of 1080–8849 books with a theoretical average ratio of 7.88 books/inmate. The real exchange ratio was 6.86 books/reader. The most preferred genre was crime by domestic and foreign authors. The results are also compared with few available studies from other countries.