Book on the Union side of the Civil War

TitleAuthor(s)My Comments & Publisher
The Catalog of Union Civil War Patriotic CoversWilliam R WeissThe definitive book on Unused CWPs with values by Weiss. Copyright 1995 and published by Weiss and still available.
Civil War Patriotic Covers Postally Used (Bischel)Nutmeg StampsThe auction catalog of the collection of Prof Jon Bischel June 2000. With price estimates at the time.
The George Walcott Collection of Civil War Patriotic CoversRobert Laurence1934 auction was the largest until Bischel. Prices in the back compiled by Luarence. Last published in 1975 in a limited addition of 750 by Robert Grant
Presidential Campaign Illustrated Envelopes and Letter Paper 1840-1872Robert W Milgram, MDOne of his series of really excellent books that covers some of the Civil War period. Published by Phillips in 1994.
Abraham Lincoln Illustrated Envelopes and Letter 1860-1865Robert W Milgram, MDOne of his series of really excellent books that covers the Civil War period. Published by Phillips in 1984.

Book on the CSA side of the Civil War

TitleAuthor(s)My Comments & Publisher
Confederate States of America
Catalog and Handbook of Stamps
and Postal History
Trish Kauffman 
Francis Crown Jr
Jerry Palazolo
Wonderful book published in 2012 by the CSA. Must have for all CSA collectors.
Dietz Confederate States Catalog
1986 Edition
Hubert Skinner
Erin Gunter
Warren Sanders
This was the main reference until the Handbook came out. Still worth having.