This must be a fascinating read. Written in 1932 and savagely censored in the process, it is the story of a forger so highly regarded that there is a collecting demand for his work, not to mention forgeries of the forgeries. Be careful you are really being offered a Joni if you are in the market for one!
The censorship was due to his telling the truth about how the forging industry in Italy was run, embarrassing no few people in the process, I dare say. What you won’t see in it is the honest truth of the involvement of the (in)famous forgery detector Bernard Berenson. You can read more about this in the NYT report accompanying a modern reprint here. In particular it explains why the 1936 first English edition is so rare:
In the early 1930s Joni revealed his intention to publish his life story; a group of Italian antique dealers got together and offered him a substantial sum to desist, but he went ahead regardless. When the English version, entitled “The Affairs of a Painter,” came out in 1936, it was cut in several places, and Berenson’s name did not once appear in the text. The book vanished with remarkable rapidity from sale, very likely, according to Mazzoni, because Berenson’s colleague Joseph Duveen managed to purchase and destroy most of the copies.
For more on this story, there is also the blog article Famous Fake Friday: Icilio Federico Joni