From considerations of spin evolution and kinematics in the Galactic potent
ial, we argue: that the pulsars B1913+16, B1534+12, and B2127+11C may be yo
unger than previously assumed, and we find that a lower bound on the format
ion and merger rate of close double neutron star binaries is 10(-6.7)f(b)(-
1)f(d)(-1) yr(-1), where f(b) is the beaming fraction and f(d) accounts for
the possibility that the known double neutron star binaries are atypical o
f the underlying population (e.g., if most such binaries are born with shor
ter orbital periods). If we assume no prior knowledge of the detectable lif
etimes of such systems, the rate could be as large as similar or equal to 1
0(-5.0)f(b)(-1)f(d)(-1) yr(-1). From both plausible bounds on f(b) and f(d)
, and a revision of the independently derived limit proposed by Bailes, we
argue that a firm upper bound is 10(-4) yr(-1). We also present a unifying
empirical overview of the spin-up of massive binary pulsars based on their
distribution in spin period P and spin-down rate (P) over dot, finding evid
ence for two distinct spin-up processes, one dominated by disk accretion, t
he other by wind accretion. We argue that the positions of binary pulsars i
n the P-(P) over dot diagram can be understood if (1) there exists a Galact
ic population of pulsars in double neutron star systems with combinations o
f spin and orbital periods that have prevented their detection in surveys t
o date; (2) recycled pulsars in wide-orbit binaries are not born near the c
anonical spin-up line in the P-(P) over dot diagram because they were predo
minantly spun up through wind accretion; and (3) there exists a disfavored
evolutionary endpoint for radio pulsars with spin periods 5-30 ms and (P) o
ver dot > 10(-19) s s(-1).