Abstract
An overview of recent developments in the understanding of thermal conduction in the cuprates is presented. Anomalous phonon damping underlies an unusual temperature dependence of the in-plane thermal conductivity for the insulating phase of some materials. This damping is sensitive to light oxygen doping in YBa
Cu
O
(YBCO), is possibly related to local structural distortions, and may persist in superconducting compositions. New systematics for the superconducting-state enhancement of K
are discussed. For YBCO the oxygen-doping dependence of the enhancement correlates with that of the pari density as determined by specific heat jumps. The large enhancements observed for fully-oxygenated specimens are attributed to pair condensation on the CuO chains. The implications of this finding and its possible connection with the emergence of the normal-state pseudogap are examined.