Anabel Thomas, Garrisoning the Borderlands of Medieval Siena: Sant’Angelo in Colle, Frontier Castle under the Government of the Nine, 1287–1355. Farnham, UK, and Burlington, VT: Ashgate, 2011. Pp. xix, 422; black-and-white frontispiece, 8 color plates, and 21 black-and-white figures. $124.95. ISBN: 978-1-4094-2603-5