Amnesia

Free to read here, from Project Gutenberg.

The man who was two men

Ray Cummings

The Return of the Soldier

Rebecca West

The S. P. Mystery

Harriet Pyne Grove

The Wiles of the Wicked

William Le Queux, also an audiobook

Mr. Petre

Hilaire Belloc

Conspiracy on Callisto

Frederik Pohl

Drifted ashore;

Evelyn Everett-Green

Captain Chaos

D. Allen Morrissey