Book excerpt: The first complete collection of all the known, non-legionary units of the Roman Army in 100 years. This volume contains information on infantry, equitata, cavalry, and naval units.Up until this time the major source for this information has been G. L. Chessman's classic work, published in 1914. Since that time a considerable amount of work has been done on those formations, and more units have been uncovered. This work organizes this information and provides an easily accessible reference to research their histories. Students and historians, both professional and amateur should find this a useful tool.