v. 1. 1916-1934.
v. 2. 1938-1964.
v. 3. [1913-1966]
OBNB doesn't sell books, but you may be able to find a copy at one of these websites:
Collected papers of P. L. Kapitza by P. L. Kapit︠s︡a. Published by Pergamon in 1964. Publication and catalogue information, links to buy online and reader comments.
obnb.uk is a Good Stuff website.