From the publisher:

The pulps' legendary superman returns in two of his greatest adventures. In Land of Always-Night, a strange being who kills with the touch of a finger leads Doc Savage on a quest to a lost underworld civilization, in an epic 1935 collaboration by W. Ryerson Johnson and Lester Dent writing as Kenneth Robeson. Then, in 1938's Mad Mesa, the Man of Bronze awakens to discover that he's in another man's body and imprisoned in a penitentiary; hundreds will die unless Doc Savage can escape and solve the mystery of the mesa madness. These thrilling pulp adventures are reproduced with the original color pulp covers by Walter Baumhofer and Emery Clarke, interior illustrations by Paul Orban and historical articles by Will Murray (who wrote 7 Bantam Doc Savage novels).