We learn from the prologue to this rare and charming little volume how true and genuine a bibliomaniac was Richard de Bury, for he tells us there, that a vehement love amor excitet of books had so powerfully seized all the faculties of his mind, that dismissing all other avocations, he had applied the ardor of his thoughts to the acquisition of books. Expense to him was quite an afterthought, and he begrudged no amount to possess a volume of rarity or antiquity. Wisdom, he says, is an infinite treasure infinitus theasaurus the value of which, in his opinion, was beyond things; for how, he asks, can the sum be too great which purchases such vast delight. We cannot admire the purity of his Latin so much as the enthusiasm that pervades it; but in the eyes of the bibliophile this will amply compensate for his minor imperfections. When expatiating on the value of his books he appears to unbosom, as it were, all the inward rapture of love.

F. Somner Merryweather, Bibliomania in the Middle Ages (Kindle edition, locations 1294-1301)