Voyage to the City of the Dead (1984) is a science fiction novel by American writer Alan Dean Foster.

Scientists Eitienne and Lyra Redowl come to the planet Horseye to study the entire length of the immense Skar River and its spectacular river chasm, the largest in the whole Humanx Commonwealth.

This treasure is eventually revealed to not be material wealth, but an ancient artifact that is used to monitor the depths of space for an approaching evil.

Dave Langford reviewed Voyage to the City of the Dead for White Dwarf #84, and stated that "Alan Dean Foster [...] offers page-turning hokum as two bickering, married scientists make their way by hydrofoil up an alien river, overcoming with ease such obstacles as the theft of their boat by hostile tribes, or attacks by ravening abominable snowmen.

Just to make sure, the author has an emergency deus ex machina waiting to save them from the final peril..."[1]