Robert Adams wrote from his personal pool of knowledge, based upon his career as a military man. He also developed a political and world view as that, and his writing often provided him a platform to express himself regarding the world, politics, religious ideals, honor, liberty, and more. The Horseclans is one of his works that would have to be regarded as his great legacy. He imagined a world devastated by wars, and not those following the timeline we know. In his world World War 3 followed relatively closely after World War 2. So as a writer in the 80s, he was writing about a world that had been devastated by a clash of nuclear arms, and rivalries, that the real world had avoided. This isn't meant to criticize his choice, simply to point out, he didn't feel obligated to pay heed to the actual timeline and present, in writing his work.
He wrote in a way that was able to express action well, but if there are flaws, there are critics who suggest that they could have done with less philosophizing and more character development. However, there is no doubt that Adams world views added to the reality and context of the battles and depth of politics and tribal interactions found in his world. The horseclans are filled with great personalities, but more great warriors. At no point for a person interested in the raison d'etre of the interaction of two tribes is there anything that could be called boring.
One of the best aspects of the works are Adams' ability to embrace the role of Barbarism in the liberating the soul of humans. Unlike the perceived goal for humans of many utopian writers, or other fantasists, high culture, great civilizations do not bring out the savage or warrior, but rather, society and civilizations subdue that in the human. Therefore, the world is seen considerably different than the nuclear super powers that had taken the world to the nuclear brink. The nuclear destruction of civilization as we know has instead liberated humanity to know its true nature.
Follow the world of the Horseclans and the new prints of the series at Mundania
The books in the US were graced with Ken Kelly covers. They were rather brilliant.