Lester Del Rey’s 1952 sci-fi novella Pursuit is all about fear.
Wilbur doesn't remember the past seven months of his life. All he knows is that someone is out to get him. Someone with a heat ray.
Del Rey makes us wait until very near the end before giving us the big reveal, and it's pretty satisfying.
A nifty little tale, tightly constructed, fast-moving with genuine existential terror.
My review: https://vintagepopfictions.blogspot.com/2021/09/lester-del-reys-pursuit.html