What does it mean?
A humorous way to show how much he loved books: they come first, and even food and clothes come second.
Who said it?
Desiderius Erasmus: Dutch scholar and humanist (c. 1466–1536).
These exact words are widely credited to Desiderius Erasmus, but they don’t appear in their known work. They may be a later paraphrase or a misattribution.