From the earliest days of motorcycling to the present time is only some twenty years or so, yet in these two decades there has been an astonishing development; improvements of which the early experimenter never dreamt are now part and parcel of every good mount. 
Performances beyond their imagination are now ordinary events. ¦. An interesting quote from inside the cover of the Douglas sales catalogue and despite the recognition of the earlier years the quote could apply to any particular period, including modern times.
By 1920 Douglas had definitely established themselves as world leaders in the supply of well engineered motorcycles. The quality of their build, their handbooks, and even their advertising brochures were of the highest standard. The start of a new decade of hopeful peacetime was well advertised by Douglas in their 1920 brochure with the front cover showing the armed forces racing for home from France on their military issue Douglas motorcycles. Acknowledgement of their war time involvement combined with unsolicited worldwide testimonials from private owners and racing successes would be hard to ignore from any prospective new purchaser. The brochure covers the 2 models available for 1920 the 2 ¾ hp W-20, and the 4 hp B-20. It also includes detailed sections of the engine drawings, diagrams of the 3 speed gearbox, and sidecars available.
Click on the engine below to see the complete sales catalogue.
It is a 3.6M PDF so you will need Adobe Acrobat Reader to view it.
