In retirement he frequently worked at the British Public Record Office, now known as The National Archives, where he discovered unpublished material on the early American colonists.
His resulting articles published in the National Genealogical Society Quarterly (NGSQ) led to his recognition and several awards of excellence.
[4] His documentation and writing of the book Passengers and Ships to America, 1618–1668 was cited by author Meredith B. Colket in 2002 as, "the most important addition to our knowledge of early New England that has appeared in over a century."
After years of painstaking research, the names of nearly all those sentenced to penal transportation were extracted from official court records by Peter Coldham and published in the landmark work The Complete Book of Emigrants in Bondage in 1988 and its Supplement in 1992, forming the largest and most complete passenger list of its kind ever published.
Questions about the peopling of colonial America come readily to mind when looking at a book like this—questions about ancestors, too—and the answers found here are both challenging and surprising.