Howard has considerable expertise in the field and has collaborated on many projects with like-minded enthusiasts. He has digitised a wealth of information and made it available to fellow enthusiasts and researchers.
I hesitate to mention Pete Young as if you visit his site you may think you've followed Alice down the rabbit hole. Honorable mention. (1)
Sergio, who hails from Argentina, has contributed numerous articles on rare and interesting machines. He tends to react with some embarrassment if referred to as an historian, so let's just say he's an ardent and thorough multilingual researcher.
Murray Barnard has developed one of the most venerable motorcycle sites on the internet, which includes a detailed listing of veteran Russian and almost all known Australian marques.
Contributed many articles on NSU and other marques written mostly in the 1990s.
Prolific photographer and author of several books on Austrian motorcycles
Denis Quinlan, aka Velobanjogent, a very knowledgeable contributor from Australia.
Steve Magro, Speedway writer and photographer.
Eric Tindal, marque specialist from the VMCC supplied information on the Moto Reve and other machines.
Carrer Aldo, afficionado. and very knowledgable in many fields, Italy. Supplied many historical photographs and specific information on rare marques. Administrator of FB group 1867-1930 Motorcycles.
One of the most useful pages on Facebook about vintage motorcycles.
Author of papers and articles on Greek history.
Journalist and Hungarian marque specialist.
Author of a comprehensive book on Czech marques and a serious enthusiast. His site includes sections on Motorcycles 1897-1918, F.N. and Laurin & Klement.
Very active in the forums, his memory for detail and depth of knowledge of the subject is often breathtaking. Nick has been enormously helpful to many in need of information on British motorcycle history.
Visit the FB page Motorcycles 1867-1930
Phil Aynsley has photographically documented a vast number of motorcycles in museums and collections around the world. A walking encyclopedia of the Italian diaspora, his image descriptions are collated from owners and curators.
Whilst not actually a motorcycle researcher, Andrew (Melbourne, Australia) has supplied many rare and interesting images, in particular from Eastern Bloc countries. His specialty is photographic art and he has compiled galleries consisting of tens of thousands of high quality images.
Many more historians and marque specialists not specifically mentioned here are referenced in the bibliography and also on the pages devoted to museums and collections.
1. Intended as humour, but sometimes it fails to translate. No disrespect intended, quite the opposite.