  Over the last few years, the number of known eclipsing radio millisecond
pulsar systems in the Galactic field has dramatically increased, with many
being associated with Fermi gamma-ray sources. All are in tight binaries
(orbital period < 24 hr) with many being classical "black widows" which have
very low mass companions (companion mass Mc << 0.1 Msol) but some are
"redbacks" with low mass (Mc ~ 0.2 - 0.4Msol) companions which are probably
non-degenerate. These latter are systems where the mass transfer process may
have only temporarily halted, and so are transitional systems between low mass
X-ray binaries and ordinary binary millisecond pulsars. Here we review the new
discoveries and their multi-wavelength properties, and briefly discuss models
of shock emission, mass determinations, and evolutionary scenarios.
