The history of the middle part of the Vietnam war using the life and experiences of John Vann, a senior military adviser, as a vehicle for the narrative. This does make the book more accessible but it also, necessarily, introduces material about Vann's personal life that I was not interested in.
I see that other reviews have described 'A Bright Shining Lie' as 'comprehensive', which is perhaps a strange description for a title that does not cover the French conflict in any detail and makes no mention at all of 'Nixon's war'.
On the whole though, this is a detailed, incisive and well-constructed analysis of US military policy and tactics during the period covered. Worthy of its Pulitzer.