'Publish' originally meant 'make publicly known' — from Latin 'publicare.' Books came later.
To make generally known; to prepare and issue a book, journal, or piece of music for public distribution.
From Middle English 'publisshen,' from Old French 'publier' (with inchoative stem '-iss-' in certain tenses, giving 'publiss-'), from Latin 'pūblicāre' (to make public property, to confiscate for the state, to make known to all), from 'pūblicus' (of the people, belonging to the people, public), from 'populus' (the people as a political body). The PIE root behind 'populus' is debated — it may connect to *pleh₁- (to fill, to be full — the people as the multitude that fills a space) or to *pō(i)- (to feed, to protect — the people as those tended by their leaders). 'Pūblicus' may additionally show the influence