  We compile observations of early-type binaries identified via spectroscopy,
eclipses, long-baseline interferometry, adaptive optics, common proper motion,
etc. Each observational technique is sensitive to companions across a narrow
parameter space of orbital periods P and mass ratios q = M_comp/M_1. After
combining the samples from the various surveys and correcting for their
respective selection effects, we find the properties of companions to O-type
and B-type main-sequence (MS) stars differ among three regimes. First, at short
orbital periods P < 20 days (separations a < 0.4 AU), the binaries have small
eccentricities e < 0.4, favor modest mass ratios <q> = 0.5, and exhibit a small
excess of twins q > 0.95. Second, the companion frequency peaks at intermediate
periods log P (days) = 3.5 (a = 10 AU), where the binaries have mass ratios
weighted toward small values q = 0.2-0.3 and follow a Maxwellian "thermal"
eccentricity distribution. Finally, companions with long orbital periods log P
(days) = 5.5-7.5 (a = 200-5,000 AU) are outer tertiary components in
hierarchical triples, and have a mass ratio distribution across q = 0.1-1.0
that is nearly consistent with random pairings drawn from the initial mass
function. We discuss these companion distributions and properties in the
context of binary star formation and evolution. We also reanalyze the binary
statistics of solar-type MS primaries, taking into account that (30+/-10)% of
single-lined spectroscopic binaries likely contain white dwarf companions
instead of low-mass stellar secondaries. The mean frequency of stellar
companions with q > 0.1 and log P (days) < 8.0 per primary increases from
0.50+/-0.04 for solar-type MS primaries to 2.1+/-0.3 for O-type MS primaries.
We fit joint probability density functions f(M_1,q,P,e) to the corrected
distributions, which can be incorporated into binary population synthesis
studies.

Solar and Stellar Astrophysics