The Tide King has a central maguffin that is very much genre - an herb that bestows immortality - that is used to explore some very weighty topics. Capital letter stuff: Life, Death, Love, Power, War, Time. Perhaps most poignantly, it explores belonging. All four of the main characters in this book are people who are out of step with the world. For two that is a product of magic; for the other two, it is simply the result of life and circumstance. The Tide King wouldn't stand without the immortality herb, and it wouldn't stand without the complex, careful weaving of points of view and points in time, and it wouldn't stand without the author's elegant observations of life. It is a literary novel with a magical, immortal, bittersweet heart.