It really depends on what type of history you would be interested in reading about.

A Bright Shining Lie - Neil Sheehan Neil Sheehan was a journalist who covered the Vietnam War, and helped to procure the Pentagon Papers for the New York Times. This book pretty much says that the whole war was run incompetently, and that everyone should be ashamed of themselves.

The Army and Vietnam - Andrew Krepinevich This book goes into why the United States lost Vietnam. Krepinevich argues that the United States didn't understand that it could never win in Vietnam without ultimately pacifying the population, and says that the United States should have focused on cutting the Vietcong off from the South Vietnamese population.

On Strategy - Harry Summers Summers and Krepinevich seem to be arguing against each other, which is why I put both books on here. Summers claims that the United States lost in Vietnam because they focused too much on counter insurgency and the Vietcong instead of traditional warfighting methods. He basically says that the Vietcong didn't matter, and that the United States should have been focusing on the North Vietnamese army.

Dispatches - Michael Herr Michael Herr was a war correspondent for Esquire magazine during the Vietnam War, and this book goes into his experiences.

The Vietnam Reader This is a big book that is a collection of both fiction and nonfiction. I like it because it shows how the stories coming out of Vietnam changes as the war goes on. It begins with a lot of gung-ho, bravado, popular culture (ballad of the green beret) and then just gets progressively darker as the United States is pulled deeper into the conflict.