That looks in my wheelhouse, Rande!
Not only a thrilling account of the fastest ride through the Colorado river in the Grand Canyon, but much of the book is dedicated to the discovery of the Colorado and boat runs through it as well as a comprehensive history of the river and the impact of the many dams that were built which contributed to the river's wild nature.
Amazing book, just incredible. Probably the finest story I've read in recent memory. Think it may have been recommended through a post of another brother here on BoB. The author paints a vivid and thrilling picture of the events and characters that bring this to life. Highly recommended!