The important corpus of Neo-Assyrian political and administrative letters discovered in ancient Calah (present-day Nimrud) by Sir Max Mallowan in the early 1950s has been partially accessible to Assyriologists in marvellous hand-copies and preliminary transliterations and translations since 1955, thanks to the pioneering efforts of the late H. W. F. Saggs. Nevertheless, his long-awaited edition of the entire corpus, which appeared in 2001, left a great deal of room for improvement. This critical edition, based on careful study of the originals in the British Museum and the historical background of the letters, clarifies a host of problems and details pertinent to the reign of Tiglath-pileser III in particular, and for the first time makes this extraordinary collection of letters completely accessible to the historian.