Thank you, SdAufKla. My reference library on military matters comprises four of five bookshelves, but as you rightly point out, the subject is so vast that represents a tiny sample. Until now, I never painted military figures and so never purchased any books dealing with personal equipment. Taking a 12 year break from serious modeling, not purchasing a single book in all that time, did not help matters.
While I own perhaps a couple dozen books from Osprey Publishing, I find they mostly attempt to cover too much ground in too few pages with too few pictures in too small a size. However, when I started researching this subject yesterday morning, one of the first things I went looking for was an Osprey book on the subject.
Which leads me to…
…
Thank you for that recommendation, Karl187. Last night, while looking for books on German World War Two military equipment, I stumbled upon the very tome you recommend and added it to my ‘Stuff to Purchase’ list. 
I’ll try to score a copy on sale somewhere.