Grandson of the Fulton Engine Genius, and Discoverer/Inventor in his own right, rides around the world on a Douglas Twin during his twenties on a bit of a lark. Out of his off-handed remark to impress a young woman we have one of the best motorcycle travel books ever written. Published umpteen times, I can imagine this book spurring on new generations of riders for decades to come.
The writing is excellent and extremely detailed, we get a breakdown of his trip during each section, along with Fulton's own sketchings and maps of the areas and people he met along the way. Photographs, of all things, to boot: images of a bike in the sea of sand, desert nomads and marketplaces; this book feeds your imagination. After 1 year of reading it a memorable item comes immediately to mind: That of Fulton being saluted and waved straight through road-blocks without stopping, to his incredulity, in occupied and dangerous Warizistan (yes, you've heard this place in the news recently), only to find that he shouldn't have made it past the first gate. It was his safari hat and fatigues that made them believe he was Indian-Army/British attache of all things. ;^)
Fulton himself is still living life with adventure. Still kicking with his old Douglas Twin and flying his own plane at the age of 87+.
If you want the best grab the first. You'll never put it down, and you'll go back a few times just to make sure you got it right when you read it there the first time.
[For other two-wheel journey books I recommend Jupiter's Travels by Ted Simon- inspiration for Ewen McGregor's recent "The Long Way Round" and Ted made the trip without cameramen and support crews!]