LISA astronomy of double white dwarf binary systems

The Laser Interferometer Space Antenna (LISA) will provide us with the largest observational sample of (interacting) double white dwarf binaries, whose evolution is driven by the radiation reaction and other effects, such as tides and mass transfer. We show that, depending on the actual physical parameters of a source, LISA will be able to provide us with a very different quality of information: for some systems, LISA can test unambiguously the physical processes driving the binary evolution; for others, it can simply detect a binary without allowing us to untangle the source parameters and therefore shed light on the physics at work. We also highlight that simultaneous surveys with Gaia and/or optical telescopes that are and will become available can radically improve the quality of the information that can be obtained.