  We summarize the quiescent X-ray observations of transient low-mass X-ray
binaries. These observations show that, in quiescence, binaries containing
black holes are fainter than those containing neutron stars. This has triggered
a number of theoretical ideas about what causes the quiescent X-ray emission.
For black hole binaries, the options are accretion onto the black hole or
coronal emission from the rapidly rotating stellar companion. There are more
possibilities for the neutron stars: accretion, thermal emission from the
surface or non-thermal emission from a ``turned-on'' radio pulsar. We review
recent theoretical work on these mechanisms and note where current observations
can distinguish between them. We highlight the re-analysis of the quiescent
neutron star emission by Rutledge and collaborators that showed thermal
emission to be a predominant contributor in many of these systems. Our
knowledge of these binaries is bound to dramatically improve now that the
Chandra and XMM satellites are operating successfully,
