Seconding this. Maniac is a beautifully written book about von Neumann. It also led me to Benjamin Labatut's When We Cease to Understand the World, another great read.

I looked at the description and this part: "Braiding fact with fiction, Benjamín Labatut takes us on a journey to the frontiers of rational thought" - gave me pause. The Braiding fact with fiction part. Are there clear demarcations between fact and fiction?