In this fifth book in the Alex Benedict series, a search for the source of an alien tablet leads to uncovering a secret others will kill to keep hidden. Somerset "Sunset" Tuttle led an adventurous but, in the end, failure-filled life. His continuous search for aliens (other than the Mutes, who don't count) resulted in endless empty hours of travel and no proof. After his death, a later owner of the house comes across a mysterious stone slab with writing never before recorded. This piques Alex's interest enough to go have a look at it, but that is nothing to the bump of curiosity that arises when the stone is stolen then dumped in the river despite the offer of vast sums of money. He and his "girl Friday", Chase Kolpath, begin to trace the history of Tuttle and those he knew regardless of who might be hurt in the process.

Written in the style of narrative non-fiction, at heart ECHO is an old-fashioned detective story told through the eyes of pilot Chase Kolpath, assistant to Alex Benedict, antiquities dealer. The future universe setting adds some glossy bells and whistles to the story line, but its real contribution is the backdrop of infinite space. It widens the questions posed in most mysteries to include greater questions asked by humanity, in the main, are we the only ones out here, and if so, why?

Despite my grandiose summation, at heart McDevitt has written an intriguing and clever mystery incorporating all the best parts of space travel and a puzzle that kept me guessing right up to the final moment. Fans of either genre will approve, and enjoy this blend of science fiction and detective story.