The Fabulous Riverboat (Riverworld )

Resurrected on banks of Riverworld, Samuel Langhorne Clemens has a dream to build a the best riverboat ever created. Then, to steer if up the endless waterway that dominates his new home planet--and at last discover its hidden source. But before he can carry out his plan, he first must undertake a dangerous voyage to unearth a fallen meteor. This mission would require striking an uneasy alliance with people of questionable reputation. All for the purpose of storming the stone tower at the mouth of the river, where the all-powerful overseers of Riverworld--and their secrets--lie in wait.