I thought there would have been a thread about this by now, but I cannot find one. If there is, Mods please feel free to move this post to the right place.
I just finished reading The Man Who Caught the Storm: The Life of Legendary Tornado Chaser Tim Samaras, by Brantley Hargrove. I would strongly recommend this book to everyone. Even though I thought I knew quite a bit about Tim before reading this book, I learned a lot by reading it, especially about the details of the various scientific research projects with which Tim was involved. The book is very well-written - I could not put it down (except to go chasing last Friday when there were finally storms within driving distance). One interesting factoid - the author was not a storm chaser before he wrote the book, but he went chasing with some of Tim's friends and colleagues as he was working on the book, to learn more about the culture of chasers - but he got hooked enough on chasing in the process that he has continued to chase since finishing the book.
You can get the book through the usual online booksellers and probably in the larger chain bookstores.