Being that today would have been his 103rd B-day, I thought this appropriate
I found the definitive biography of him by Individual Anarchist/Poet John Henery Mackay; the English translation is new, it was only done in 2005, on amazon here: .
Also, here is a free online version of Macay’s book “The Anarchists”, it was published by Benjamin Tucker in America:
http://dwardmac.pitzer.edu/Anarchist_Archives/macan/macan.html