This week's Tor Free E-Books Giveaway is "Starfish", by Peter Watts.
"Starfish" is the first book in the Rifters Trilogy. Amazon reviewers give it 4 1/2 stars out of 5. You can find out more about Peter Watts at Rifters or on his wikipedia page.
A synopsis (from Amazon):
Set in the early 21st century, Watts's debut describes a future when the search for energy leads to the tapping of geothermal sources deep in the ocean, as in the Pacific's Juan de Fuca Rift, near Canada's Northwest coast. The maintenance workers of the dangerous underwater power plants are selected for their psychotic tendencies, which enable them to forget their previous lives on dry land, and are then surgically altered to survive the intense pressure of the sea's abyssal depths.
Of course, it sounds as if things don't go so well for our maintenance workers, though I also didn't get a vibe that this was another Abyss. The use of technology is "superb", and the workers are as much a part of the salvation as they are the destruction of the people who live at the surface.
It sounds like a worthy read.
For a running list of all of Tor's free e-books, go here.