The quark contribution to the free energy of a hot quark-gluon plasma is ca
lculated to leading order in hard-thermal-loop (HTL) perturbation theory. T
his method selectively resume higher order corrections associated with plas
ma effects, such as screening, quasiparticles, and Landau damping. Comparin
g to the weak-coupling expansion of QCD, the error in the one-loop HTL free
energy is of order alpha(s), but the large alpha(s)(3/2) correction from Q
CD plasma effects is included exactly.