Cool Stars 14 - Submitted Abstract # 129 This version created on 05 October 2006 Ages for illustrative field stars using gyrochronology Sydney Barnes, Lowell Observatory Gyrochronology is the technique of deriving ages for solar- and late-type main sequence stars using their rotation periods and colors. In addition to allowing the derivation of ages for individual field stars, it permits the derivation of the errors on those ages, which are estimated to be ~15% for individual G, K, and M stars. (This poster summarizes the results of a paper in the Astrophysical Journal which explains gyrochronology in detail.) ----------------------------------