I recently came across an excellent survey article, “Morse Theory Indomitable“, by Raoul Bott. It starts with the basic history of Morse functions, and covers the additions of Smale and Witten, and the connections to symplectic reduction. Though, even moreso than being a clear and concise overview of some beautiful mathematics, it is all liberally dosed with personal anecdotes from the life of someone who lived throughout virtually the entire story. It was a throughly enjoyable read, even though I had seen almost all the contained math before.
Morse Theory Indomitable