You will be purchasing all 14 volumes currently available:
Volume I, Historical Records
Volume II, Abbott to Burtch
Volume III, Burtis to Dakin
Volume IV, Darbyshire to Everitt
Volume V, Fackert to Haas
Volume VI, Hadden to Hunt
Volume VII, Hunter to Leavens
Volume VIII, Lee to Millington
Volume IX, Mills to Page
Volume X, Paine to Rogers
Volume XI, Rood to Sly
Vol. XII, Smith to Spaulding
Vol. XIII, Spencer to Swift
Vol. XIV, Taber to Tupper