From the publisher:
Psychopomp is the result of 30 years of art created by Wayne Barlowe
Inspired by Milton's Paradise Lost, Wayne Barlowe spent 30 years building his own underworld, his book includes more than 100 illustrations and 150 character designs, sketches, and countless daily notes of his creation. Many pieces have never before been published.
Well known (and very much appreciated) by the cinematic universe, he participated to numerous projects such as: Avatar, Pacific Rim, the Harry Potter series, the Hellboy series, Blade III, and Galaxy Quest.