The mistaken tradition that Rev. Thomas Barclay of Albany was the son of John Barclay of East New Jersey is investigated based on an examination of records from East New Jersey, records from Bury Hill, Surry, and records in London. Subsequent discussions focus on the line of descent from John Barclay, the Dublin branch of the Barclays of Ury, the line of descent from Thomas Barclay of Maryland, the line of descent from Rev. Thomas Barclay of Albany, John Barclay of Londonderry and sundry lines of descent of Barclays (and Barkleys). The text is enhanced by extracts from New York City directories (1786-1803), a partial table of descent of the Barclays of Ury, sundry records of Barclays in Ireland and miscellaneous records from New York, New Jersey, Pennsylvania, Maryland and Virginia. Genealogical entries are arranged by line of descent. Numerous excerpts from original documents, appendices, and full name indices for individuals with the surname of Barclay, Barkley, and surnames other than Barclay add to the value of this work.