The Philatelic Book of Secrets Vol. #3, published by Professional Stamp Experts (PSE), is an essential reference for collectors of pre-1940 stamps. It discusses color varieties on U.S. stamps. Book is brand new except has some damage on outside cover that occurred during mailing and id repaired by clear tape (see scans).
PSE's The Philatelic Book of Secrets Vol. #3 - Essential Reference
This item is returnable, for any reason, for up to 30 days from the date of mailing as long as it is returned in the same condition as it was sent.