  Multiwavelength opportunities have provided important new insights into the
properties of binary/multiple 5 Msun stars. The combination of cool evolved
primaries and hot secondaries in Cepheids (geriatric B stars) has yielded
detailed information about the distribution of mass ratios. It has also
provided a surprisingly high fraction of triple systems. Ground-based radial
velocity orbits combined with satellite data from Hubble, FUSE, IUE, and
Chandra can provide full information about the systems, including the masses.
In particular, X-ray observations can identify low mass companions which are
young enough to be physical companions. These multiwavelength observations
provide important tests for star formation scenarios including diffenences
between high and low mass results and differences between close and wide
binaries.
