  The millisecond pulsar in a triple system (PSR J0337+1715, recently
discovered by Ransom et al.) is an unusual neutron star with two orbiting white
dwarfs. The existence of such a system in the Galactic field poses new
challenges to stellar astrophysics for understanding evolution, interactions
and mass-transfer in close multiple stellar systems. In addition, this system
provides the first precise confirmation for a very wide-orbit system of the
white dwarf mass-orbital period relation. Here we present a self-consistent,
semi-analytical solution to the formation of PSR J0337+1715. Our model
constrains the peculiar velocity of the system to be less than 160 km/s and
brings novel insight to, for example, common envelope evolution in a triple
system, for which we find evidence for in-spiral of both outer stars. Finally,
we briefly discuss our scenario in relation to alternative models.
