This is my favorite of Lackey's books, her most moving and heartfelt. It famously has a gay protagonist, rare even in speculative fiction, even in these days. Gay characters aren't unusual, especially now, but gay protagonists still are.
Those themes are important in this book and trilogy, and I think it explores it in ways that are thought-provoking and stayed with me as a young woman. Back then in 1989 when this came out, before Buffy and Will and Grace I can remember very few positive depictions of gays in fiction. My mother certainly wouldn't have approved of the subversive notions under the innocuous cover with the pretty guy hugging a white horse.
However, although I do think this theme is part of what gives the Last Herald Mage novels emotional punch, it doesn't pound the narrative to pieces; the book doesn't feel preachy. It's just a good adventure, fantasy story, set in a pseudo-medieval world of "heralds" who are a police/military force chosen by seeming horses, magical creatures that can see into someone's character and are full partners--it's simply a good read.
