This book represents a massive undertaking and a significant achievement in Welsh-American studies. Citing correspondence and other documents on religion, government, military matters, business, law, and medicine that are in the Manuscript Collection of the Historical Society of Pennsylvania, author Marcella Biro Barton has compiled an extensive bibliography of Welsh names covering the colonial period through the 20th century. The vast number of entries dating to the colonial period demonstrates the importance of the Welsh in the British settlement of Pennsylvania, in particular around the city of Philadelphia. Including people from all socioeconomic levels, the citations bring to the life the social fabric of this important region in American history. Barton's work represents an excellent source for those doing genealogical research or those interested in the social, political, or economic history of this region.