Full disclosure: I am recommending a book that a friend wrote. Robert Grenier, who spent over 30 years as a career C.I.A. officer, was the station chief in Islamabad, Pakistan, during 9/11. In that position, he helped plan the U.S. invasion of Afghanistan. He also served as chief of the Iraq Issues Group where he was one of the individuals who coordinated the covert operations that supported the U.S. invasion of Iraq. His last position was as Director of the Counterterrorist Center.
His book, 88 Days to Kandahar, A CIA Diary, is excellent. It not only gives a very concise history of the machinations of the U.S. government and the players within the intelligence community but it also details the entrance into the invasion almost minute by minute. He writes about both the Pakistani players and the Afghanis with insight and understanding of the personalities and the culture that is humorous as well as accurate.
This book is a must-read for any student of history or anyone interested in how the intelligence community functioned during one of the most interesting times in recent American history. It also has the advantage of being well-written and a page-turner!