Reginald Bretnor’s The Future at Waris a trio of military SF anthologies. The series consists of Thor’s Hammer(1979), The Spear of Mars (1980), and Orion’s Sword (1980). The three anthologies provide an interesting look at early military SF, which was still in a rudimentary form at this point.
[NOTE: I originally posted an older draft of this. My apology for my error]