In this report, we present a full study of the statistical mechanics o
f the zero-field and magnetized pair-boson and pair-fermion gases in d
spatial dimensions. An extensive literature has developed over the pa
st decade on the zero-field pair gases. These studies are extensively
reviewed and further developed, and we give explicitly results for var
ious thermodynamic functions, such as the specific heat. For the Bose
gas, this allows us to give a thorough exposition of d-dimensional pai
r Bose-Einstein condensation. The generalization to an original study
of the statistical mechanics of the magnetized pair quantum gases form
s the remaining body of this report. The results presented give a comp
lete investigation, again in d-dimensions, of these systems which are
considerably more intricate than their zero-field counterparts. For th
e Bose gas, we show that although Bose-Einstein condensation does occu
r tor all d greater-than-or-equal-to 5, the magnetization for all d gr
eater-than-or-equal-to 3 is remarkably different in form to that of th
e nonrelativistic Bose gas. There is still a Meissner effect, but of a
new nature; in fact magnetized pair Bose systems are relativistic sup
erconductors. In the case of the zero-field pair Fermi gas, we review
the existing literature, and develop expansions for various thermodyna
mic functions. For the pair-fermion-gas in an external magnetic field,
we find new results for relativistic para/diamagnetism. In this case,
the effect of intrinsic spin upon the magnetization is an important o
ne. For both systems, external fields ranging in strength from weak to
extremely strong are considered. The physical scenarios for the manif
estation of these systems are thus many, and include exotic stellar ob
jects in the present epoch, and cosmology and the early universe. Usin
g these contexts as a background, the emphasis of this report is on th
e statistical mechanics of pair systems. The Mellin-transform techniqu
e is used to develop expansions for the thermodynamic functions, and w
e give a full presentation of this and other analytical machinery that
is necessary to deal with the inherent mathematical intricacy of calc
ulating the relevant thermodynamic functions. This complete study of t
he zero-field and magnetized Bose and Fermi gases allows comparison be
tween th effects of critical phenomena, thermal pair creation, statist
ics, spin, and external fields upon the macroscopic behaviour of these
fundamental pair systems at temperatures above pair threshold.