Glen Cook has written a number of very good fantasy books, as well as some uneven (imo) science fiction. As time goes on, his books become more and more directly based on historical settings -- as opposed to books in settings he created himself with incidents based on battles that actually happened. This style where he takes an overall series of events and adapts it to his own world-building and story works well for him, because the stories he tells are intensely personal histories and not top-down descriptions of events.
The Tower of Fear is more or less based on incidents from the Punic Wars with the three contending groups in the story representing Romans, Carthaginians, and desert nomads. However, due to Cook's storytelling style, this is all irrelevant information, all motives in the story are base human ones.
This is essentially a story about family and love that involves terror, death, destruction, and magic. It's probably good for people who like fantasy and/or military fiction from the mid-teens on. Magic is an important part of this book, but it is only in the background. There's lots of killing and etc... but the antiheros and twists of the book tend more towards clever than dark. Well worth reading if you like character-driven fantasy that isn't all about quests, coming of age, and crapping around after world-saving artifacts.