I have not read this book but it seems to offer insights into the institution, politics and professionalism, section on Iraq DoS engagement, org chart.

Career Diplomacy: Life and Work in the U.S. Foreign Service
by Harry W. Kopp (Author), Charles A. Gillespie (Author) October 2008

Table of contents - http://www.amazon.com/gp/reader/1589...pt#reader-link