I've never seen the Berlin book, but, apparently, it's an encyclopedia of just about everything one could want to know about the character and his world. The Hanke book is pretty good. Dosen't go into quite as much behind the scenes detail as I'd like, but what IS there is well written. Hanke was quite annoyed that McFarland wouldn't let him correct a small handful of very minor errors (one or two were no more than typos) before they reprinted the hardcover as a trade paperback