Unseen Tools

From Author Wars - https://authorwars.com/books/unseen-tools-114422.html

Overview:

Title: Unseen Tools
Author: Leo Vernon
Year: 1940
Type: Essays

Editions/Publications:

Unknown. Astounding Science-Fiction, June 1940 (Unknown, Leo Vernon, Street & Smith Publications, Inc., $0.20, 164 pages, pulp, MAGAZINE)
Unknown. Astounding Science-Fiction, June 1940 (Unknown, Leo Vernon, Atlas Publishing and Distribution Co. Ltd, -/6, 80 pages, pulp, MAGAZINE)