Major Jones's sketches of travel, comprising the scenes, incidents and adventures in his tour from Georgia to Canada Book

As you probably already know, this book is narrated by an immortal atom living in the pineal gland of an eighteenth-century London haberdasher, who dictates the story of his life in eighth-century Japan, back when he lived in the butt of a Japanese official and consequently was "privy" to affairs of state. The story he tells is a thinly veiled allegory for the (then-contemporary) Seven Years War, with Japan=Britain, China=France, etc.

The result is as weird as you imagine. Unless you have a doctorate in eighteenth century politics, you'll probably want an edition with extensive notes (e.g. this one) to understand the barest amount of what's going on; even with notes, the book is difficult to read because for every character you must remember 1. a long and absurd pseudo-Japanese name and 2. a "real world" equivalent, whose name and function is only occasionally familiar to a layman.

When it works (which is not so very often) though, the book offers wonderful examples of grotesquery:

"He put them upon a diet of yeast; where this did not agree with the stomach, he employed his emissaries to blow up the patients à posteriori…The individuals thus inflated were seen swaggering about the streets, smooth and round, and sleek and jolly…"

or absurdity:

"[After the death of a commander] 'Tis an ill wind that blows nobody good:'the same disaster that deprived him of a good officer, afforded him the opportunity to shift the blame of neglect from his own shoulders to those of a person who could not answer for himself."

Smollett makes a pretty good attempt to out-Rabelais Rabelais by throwing in ludicrous erudition mixed with nonstop scatology; but the very specific local interest of much of the allegory keeps it from hitting the Gargantuan heights. More a curiosity with flashes of brilliance than a must-read.