Failure of Empire by Noel Emmanuel Lenski

The author in his epilogue states that his purpose in writing this book was to show the change in dynamics that a late Roman Emperor would have had to face and deal with and personally. I think he does an excellent job. He relies on primary sources such as Zosimus, Ammaianus and the Annonymous to name a few as well as several contemporary works by such historians as Peter Heather, AHM Jones and Ramsey MacMullen. The book is around 400 pages long and covers every aspect of the reign of Valens, (as well as his brother in the West Valentinian), from how they came to power, to the end of Valens reign. He covers the challenges Valens faced from simply being of Pannonian birth and of the extreme exertion of will needed to govern the East during the 4th century.