Membership in the National Society Colonial Daughters of the 17th Century is based upon descent from 17th-century ancestors who imperiled their lives and interests in various colonial wars from May 1607 to December 1699, and rendered other distinguished services. The 1989 and 1999 Lineage Books are similar in arrangement, but their contents differ owing to the passage of time. Both volumes are divided into two parts: (1) A list of living members and their qualifying ancestors, followed by (2) brief sketches of the roughly 2,500 17th-century ancestors, with the names of living members of the organization, if any, descended from them.