Sherman is a wonderful novel that is one of the most unusual books I’ve ever read. It’s equally science fiction and historical fiction, but it's also full of post-modern satire. Like history, it refuses to be categorized into any single category. It reads like Cloud Atlas with a touch of Idiocracy and Sliders, but goes beyond those limitations.
Time travel in the book is a narrative device to fuel a post-modern deconstruction of grand historical narratives. If someone wants a novel that, like Poseidon, constantly changes as you try to grab onto it, full of scientific discoveries and the weirdest, wildest plot you've read, you've got that. For those who want a deeper, philosophical inquiry into our current political milieu, fueled through the perspectives of both the powerful and the powerless, you've got that as well. Masterfully done.