Well, despite my best efforts to put off the day when I came to the last page, I have finished Charles Portis's Masters Of Atlantis (as mentioned in Sax Rohmer... below), and I can confirm that it is indeed the funniest book (new to me) that I've read in many years - so funny that it's had me laughing aloud in public and private places, and urging everyone I know to read it. It's hardly a 'comic novel' in the conventional sense: there is no striving after comic effects, and the setting up of comic situations is so subtly done as to be unnoticeable. The actions and thoughts of the deluded protagonists are to them perfectly serious, and Portis tells it straight, describing what is going on in impeccably deadpan tones. The thing is that what these people are doing and thinking happens to be inherently very funny, and need only be described in Portis's spare, dry, perfectly judged language - and wonderfully sharp dialogue - to become comedy.
Masters of Atlantis tells how Lamar Jimmerson, stationed in France at the end of the Great War, finds himself in possession of a booklet that he takes to be a summation of the lost wisdom of Atlantis. It has come to him, he believes, from one Pletho Pappus, Master of the Gnomon Society - though his efforts to find Pletho on the island of Malta and make himself known to him by various signs come to nothing. It is on Malta, though, that he crosses the path of Sydney Hen, an English aesthete, who pounces eagerly on the Ancient Wisdom, and is clearly bent on dominating the long-suffering Jimmerson. The seeds of the inevitable great schism in Gnomonism are already being sown....
What follows tells mostly of Jimmerson's establishment of a thriving (for a while) Gnomon Society in America - an endeavour in which he is much assisted by the silver-tongued bull artist Austin Popper, a man with a remarkable ability both to get into scrapes and to talk himself out of them (or, in extremis, take to his heels). He is the agent of motion in the narrative, in contrast to the increasingly torpid Jimmerson, and Popper's adventures give the novel much of its forward momentum - his spell in the Rockies with a Romanian crackpot called Golescu, attempting to extract gold from bagweed, is particularly rich in comic incident. But enough. Perhaps the best thing would be to offer a sample paragraph - here's one from early in the story, when Jimmerson and a go-ahead fellow Gnomon, Bates, are looking to extend the reach of their glorious movement:
'Bates too pitched in anew. Through a friend at the big Chicago marketing firm of Targeted Sales Inc, he got his hands on a mailing list titled 'Odd Birds of Illinois and Indiana', which, by no means exhaustive, contained the names of some seven hundred men who ordered strange merchandise through the mail, went to court often, wrote letters to the editor, wore unusual headgear, kept rooms that were filled with rocks or old newspapers. In short, independent thinkers, who might be more receptive to the Atlantean wisdom than the general run of men. Lamar was a little surprised to find his own name on the list. It was given as 'Mr Jimmerson'. His gossiping neighbours in Skokie, it seemed, had put him down as an odd bird. They had observed him going into his garage at night in a pointed cap and had speculated that he was building a small flying machine behind those locked doors, or pottering around with a toy railroad or a giant ball of twine.'
The pointed cap, by the way, is the Poma, a conical cap denoting high Gnomon authority. Even at the end, when the Gnomon Society is sadly reduced, Jimmerson is still wearing his increasingly moth-eaten Poma - and 'Still the eye was drawn to it'.