  White dwarf binaries are the most common compact binaries in the Universe and
are especially important for low-frequency gravitational wave detectors such as
LISA. There are a number of open questions about binary evolution and the
Galactic population of white dwarf binaries that can be solved using
gravitational wave data and at the same time, our ever improving knowledge
about these binaries will help to predict the signals that can be expected for
LISA. In addition a number of white dwarf binaries will serve as verification
sources for the instrument. I will discuss these issues and report recent,
surprising, developments in this field. Finally I report calculations about the
feasibility of complementary electro-magnetic observations which unfortunately
cannot reproduce the optimistic results of Cooray et al. (2004).
