  We summarize the results of our long-running campaign to help understand the
nature of high-mass X-ray binaries (HMXBs), emphasizing recent Suzaku
observations of IGR J16207-5129 and IGR J17391-3021. Thanks to the expanding
ranks of HMXBs in our Galaxy, we are able to perform more reliable statistical
analyses on the three currently-known sub-classes of HMXB: those with
supergiant companions (SGXBs); those with Be companions (BEXBs); and the
enigmatic Supergiant Fast X-ray Transients (SFXTs). We discuss new diagnostic
tools, akin to the "Corbet diagram," in which HMXBs tend to segregate based on
their dominant accretion mechanism. We show how SFXTs span across the divided
populations of BEXBs and SGXBs, bolstering the intriguing possibility that some
SFXTs represent an evolutionary link. The use of HMXBs as tracers of recent
massive star formation is revisited as we present the first ever spatial
correlation function for HMXBs and OB star-forming complexes. Our results
indicate that at distances less than a few kpc from a given HMXB, it is more
likely to have neighbors that are known massive-star forming regions as opposed
to objects drawn from random distributions. The characteristic scale of the
correlation function holds valuable clues to HMXB evolutionary timescales.
