Start with high-confidence military uniforms books, then narrow by subgenre or adjacent topics.
The Illustrated World Encyclopedia of Knives, Swords, Spears & Daggers: Through History in Over 1500 Photographs
Harvey J.S. Withers, Tobias Capwell
Modern African Wars (5)
Philip Jowett, Raffaele Ruggeri
The Athenian Army 507-322 BC
Nicholas Sekunda, Giuseppe Rava
Central European Wars 1918-21
Philip Jowett, Adam Hook
