Description: Alpha Tau Omega Fraternity national membership records, including early Official Registers initially compiled by "Second Founder" Joseph R. Anderson (ca. 1878-91), arranged by chapter and members' place in chapter rolls; Chronological Records (ca. 1892-1900), which assigned the first ("A-series") national membership numbers; Numerical Record Ledgerbooks (ca. 1900-16) used by Worthy Keeper of Annals William C. Smiley to establish a new system, arranged by "WGKE [Treasurer] number"; National Numerical Register (ca. 1916-84), arranged by membership number; and National Register of Chapter Membership (ca. 1916-84), arranged by chapter affiliation. Each record-keeping system attempted to be retrospectively complete to ATO's founding in 1865. The National Registers, along with the ATO Membership Card Files (record series 41/92/15), constitute the authoritative membership records until the computerization of records in the early 1980's. Also includes Membership Rosters and The Form (forms for reporting new initiates, new pledges, new officers, or membership changes).