The earlier book-length biography by Norman Macrae is quite terrible imho. This new one (per photochemyn's comment in this thread) doesn't sound that promising either, unfortunately, and few of von Neumann's contemporaries are still around to talk to.
There is a German guy (Ulf Hashagen) who has done some excellent biographical research about von Neumann. I hope he writes a full length biography some day, since there doesn't seem to be one now. Meanwhile, the best overview article I know of is Stanislaw Ulam's profile in the AMS Bulletin published shortly after von Neumann's death, in the special issue devoted to him:
There is a German guy (Ulf Hashagen) who has done some excellent biographical research about von Neumann. I hope he writes a full length biography some day, since there doesn't seem to be one now. Meanwhile, the best overview article I know of is Stanislaw Ulam's profile in the AMS Bulletin published shortly after von Neumann's death, in the special issue devoted to him:
https://projecteuclid.org/journals/bulletin-of-the-american-...