Ask Hugo- and Nebula-winning science fiction writer Mike Resnick which works out of his scores of novels and hundreds of award-winning shorter pieces does he feel represents his best work. He has two answers, "the next one" (all writers say that) and, more reflectively, he answers "Paradise, Purgatory, and Inferno."
Ask any reviewer familiar with Mr. Resnick's astounding and significant additions to the classic literature of speculative fiction over the past 40 years and you get the same two answers--"his next" (because new Resnick books are always eagerly awaited) and, taking your question more seriously, "Paradise, Purgatory, and Inferno." These three novels both entertain and provoke thought on various levels. First and foremost, you'll find satisfying adventure on distant and unique worlds. But are they so different and unique? If you know anything of the history of Africa (and Resnick is an acknowledged expert) you'll find parallels provoking thought and providing understanding. If you know nothing of Africa, you will.