American Society of Military Insignia Collections which was organized in 1937 to promote the collecting of military insignia.

This is their publication, TRADING POST, Vol XXX111 October-December 1973. 100 pages.

There are 100 pages of information on insignias.
Back cover is printed: Shoulder Sleeve Insignia, London Base Command, World War II (insignia)
Front cover: Distinctive Insignia Air Corps Advanced Flying School (insignia)

There is page after page of insignias.  This is a great reference book for the person who collects military items.