Ludwig von Mises, notes and recollections Book

A moving and intimate book from a genius who "set out to be a reformer, but only became the historian of decline."
I believe one cannot fully understand Human Action: A Treatise on Economics unless one has read this one. It is the book that puts Mises's life into perspective, from his own point of view, at a time when he was desolate and really without knowing what would happen next in his life.
He had been through so much and now was 60 years old, alone with his wife, having to find his way in a new country (USA), where his old imperial Austrian prestige would only be a further burden.
There's also some interesting theoretical discussions on the method of economics.
So, all in all, an essential book for everyone who wants to understand the Austrian Economics movement.

for a nice short comment on this book's relevance, see this post by Peter Boettke: