Trio of Sorcery consists of three fantasy novellas by Mercedes Lackey, who writes the Diana Tregarde series and is co-author (with Andre Norton) of the Half-Blood Chronicles. In each tale, a strong female protagonist with paranormal powers comes up against an equally powerful villain and has to round up a crew, take on the villain and triumph before an innocent person becomes the victim of an evil force. Each novella is set in a different, though recent, time period and features a different set of paranormal powers.

In the first, Arcanum 101, which is set in the early 1970s, Diana Tregarde is a student at Harvard, where she is trying to live a normal life, keeping secret the fact that she's a practicing witch. A Boston cop, though, at a dead end on a kidnapping case, knows about her abilities and asks for her help. The victim's mother, it seems, has fallen under the influence of a phony psychic, which is affecting the progress of the case. Diana agrees to help and, soon, with the aid of three Harvard students she befriends, is deeper into a psychic war than she could imagine herself.

For the second, Drums, Lackey takes us to the southwest in the '90s, where Jennifer Talldeer, an Osage Indian, who is both a private detective and a shaman, takes on the case of a young Chickasaw woman who has fallen under the spell of an Osage ghost who has set out to make her his bride and is willing to destroy anyone who gets in the way. He draws strength by vampiring it from his victim through native dancing. Talldeer, with her partner and her grandfather, another shaman, must fight the ghost for the spirit of the woman.

Finally, in Ghost in the Machine, we enter the present day, where Ellen McBride, gamer and computer specialist, is what the book's liner notes call "the world's first techno-shaman." Hired to debug a new program, she discovers that the game's servers have what you might call stacked the deck by breaking the barrier between the natural and supernatural worlds. Again, McBride and her crew must set things straight.

I mention the time period for each one because it is a factor in the telling of the stories. In two of them, we are in a world with no cell phones, cable TV, video games, personal computers or anything of that sort. The third, which enters today's world and contains and uses all of our modern features, is actually the weak link in the trilogy of tales. The ones that are more remote from our time are more imaginative.

I'm describing these stories in terms of their plots, but that, of course, is not all there is to them. Lackey is skilled at setting conflict into motion, careful to balance the forces so that the outcome is in doubt, and she creates characters with enough reality to them that you can believe while you're reading. In fact, since all three plots rely on the same basic formula, the other values of the stories have to carry the day. It's a testament to Lackey's skill that they do.