The Shrinking Man by Richard Matheson [BERKLEY PAPERBACK / 1979]
The Shrinking Man by Richard Matheson
VINTAGE PAPERBACK  BERKLEY BOOKS
1st berkley printing.
Solid reading copy with some heavy shelf wear and creasing to cover. Inside reads as new.
While on holiday, Scott Carey is exposed to a cloud of radioactive spray shortly after he accidentally ingests insecticide. The radioactivity acts as a catalyst for the bug spray, causing his body to shrink at a rate of approximately 1/7 of an inch per day. A few weeks later, Carey can no longer deny the truth: not only is he losing weight, he is also shorter than he was and deduces, to his dismay, that his body will continue to shrink. - Bookshop Apocalypse