He is remembered mainly for having authored Il libro dell'arte, often translated as The Craftsman's Handbook. Written in the early 15th century, the book is a "how to" on Renaissance art. It contains information on pigments, brushes, panel painting, the art of fresco, and techniques and tricks, including detailed instructions for underdrawing, underpainting and overpainting in egg tempera. Cennini also provides an early, if somewhat crude, discussion of painting in oils. His discussion of oil painting was important for dispelling the myth, propagated by Giorgio Vasari and Karel Van Mander, that oil painting was invented by Jan van Eyck (although Theophilus (Roger of Helmerhausen) clearly gives instructions for oil-based painting in his treatise, On Divers Arts, written in 1125).
The dates of Cennini's life are highly speculative. It is often falsely assumed that he was alive in 1437 because that date appears on one of the copies of his manuscript. This is discussed by Daniel V. Thompson in the preface to his authoritative translation of Il libro dell'arte. Thompson himself does not speculate on Cennini's years of life, a sure indication of the lack of evidence on this point. Thus, dating Cennini's book to the "early 15th century" as above is only a guess. The techniques Cennini describes are grounded in the late 13th and mid 14th centuries. There is no evidence in his writing of the exciting developments in oil painting taking place in the early 15th century. This suggests that his book was indeed written sometime in the 14th century.