Chase the Morning, by Michael Scott Rohan
Steve is a Import/Export executive in a nameless British city. His impulsiveness, curiosity, and good turn to a stranger lead him to learn of a greater and more magical world just around the corner from our own. Our world, the Core is the center point of a seemingly limitless sea of lands of magic and adventure.
Voodoo, strange magic, demigods, and sea adventure a la Horatio Hornblower are the order of the day, as Steve, at first unwillingly, learns more about this strange secret outer world on its magical high seas.
Hollow inside, Steve grows and learns what it is to be a man and take responsibility through his adventures with his odd, new companions. Certainly, the book at its main is the trope of "modern man thrown into a fantasy world" but the intersection of those worlds, their dependence on each other, and the vividness of the descriptions (especially the battle scenes) make the novel work. I know now why my friend Scott seeks out novels from this British author, even though they can prove difficult and expensive to obtain here in the states.