Dorsai Trilogy Series by Gordon R. Dickson

It's obvious that Cletus Graeme--limping, mild-mannered scholarly--doesn't belong on a battling field, but instead at a desk working on his fourth book on battle strategy and tactics. But Bakhalla has more battlefields than libraries, and Graeme sees his small force of Dorsai--soldiers of fortune--as the perfect opportunity to test his theories. But if his theories or his belief in the Dorsai lead him astray, he's a dead man.

A Hugo Award-winning novel of destiny and revenge. On the sixteen colonized worlds, mankind had changed: men of War on the Dorsai worlds, men of Faith on the Friendly worlds. Jamethon Black, a Friendly, is a true soldier, and a true man of faith. Now he must face a deadly enemy--an enemy whose defeat will forever separate him from the only woman he has ever loved.

aka The Genetic GeneralThroughout the Fourteen Worlds of humanity, no race is as feared and respected as the Dorsai. The ultimate warriors, they are known for their deadly rages, unbreakable honor, and fierce independence. No man rules the Dorsai, but their mastery of the art of war has made them the most valuable mercenaries in the known universe. Donal Graeme is Dorsai, taller and harder than any ordinary man. But he is different as well, with talents that maze even his fellow Dorsai... moreaka The Genetic GeneralThroughout the Fourteen Worlds of humanity, no race is as feared and respected as the Dorsai. The ultimate warriors, they are known for their deadly rages, unbreakable honor, and fierce independence. No man rules the Dorsai, but their mastery of the art of war has made them the most valuable mercenaries in the known universe. Donal Graeme is Dorsai, taller and harder than any ordinary man. But he is different as well, with talents that maze even his fellow Dorsai. And once he ventures out into the stars, the future will never be the same. less