Yes, I’m reading this book.
The Flow is not anything close to a river—it is a multidimensional brane-like metacosmological structure that intersects with local time-space in a topographically complex manner, influenced partially and chaotically but not primarily by gravity, in which the ships accessing it don’t move in any traditional sense but merely take advantage of its vectoral nature, relative to local space-time, which, unbounded by our universe’s laws regarding speed, velocity, and energy, gives the appearance of faster-than-light travel to local observers.