We present a summary of the splinter session on "touchstone stars" -- stars
with directly measured parameters -- that was organized as part of the Cool
Stars 18 conference. We discuss several methods to precisely determine cool
star properties such as masses and radii from eclipsing binaries, and radii and
effective temperatures from interferometry. We highlight recent results in
identifying and measuring parameters for touchstone stars, and ongoing efforts
to use touchstone stars to determine parameters for other stars. We conclude by
comparing the results of touchstone stars with cool star models, noting some
unusual patterns in the differences.Comment: Proceedings of the 18th Cambridge Workshop on Cool Stars, Stellar
Systems, and the Sun, Eds G. van Belle & H. Harri