This article surveys many aspects of the theory of quandles which
algebraically encode the Reidemeister moves. In addition to knot theory,
quandles have found applications in other areas which are only mentioned in
passing here. The main purpose is to give a short introduction to the subject
and a guide to the applications that have been found thus far for quandle
cocycle invariants.Comment: Submitted to conference proceedings; embarrassing misspellings of
various names corrected. Many apologies and thanks to readers who pointed out
correction