A novel written in 1996 by Andrew Crumey. Published by Picador USA. 203 pages long, counting an introduction by John Clute. It is divided into three sections (panels), each with characters and events only distantly related to the other.

The first panel, and the longest, at 87 pages, is about the title character, Jean Le Rond D'Alembert, and his life. This panel is actually given from two perspectives, the first being that D'Alembert is an aging, senile man writing his memoirs, and that his maid, Justine, is sneaking around and reading them. The second perspective is from his perspective, living his life. The story stays fairly close to D'Alembert's actual life, from his working on the Encyclopedie with Rousseau and Diderot, and his obsessive love with Julie D'Espinasse, a young upstart in the French intellectual life, who did not return his love, and in fact had a love affair with a Spanish nobleman. The second part of this panel is taken up by letters written by D'Alembert, Julie, and occasionally others. It ends with Justine finding him dead, while working on his memoirs.

The second panel is about Magnus Ferguson, another real person. This one is only 36 pages long, and dabbles in the realm of strange science fiction. Ferguson, dreaming? delirious? who knows? apparently is in a mansion that he doesn't know, and presumes he is dreaming. He meets the owner, who tells him that he has been here for years, and actually died yesterday. Ferguson then goes into his workshop, and finds some papers supposedly written by him. Every day he returns to the workshop, he finds new papers. These papers describe trips to the planets, and meeting the societies that live there. At the end, he finds a letter, written to himself, from the Ferguson that supposedly lived there. Workshop Ferguson tells Dreamer Ferguson that he died of typhoid, but that Dreamer can take his place. It is never resolved whether or not he was dreaming the whole thing.

The third section of D'alembert's Principle is entitled Tales of Rreinstadt. Apparently, Rreinstadt was a city in another one of Crumey's books. The main character is Goldmann, a wealthy jeweller who takes a walk. He visits Heinrich the baker, who has been half insane since he was run over by a cart five years ago. When he arrives, he finds Heinrich dead, and speaks to Heinrich's brother, Marcus, who explains that Heinrich was once one of the greatest bakers in the world, but lost his touch after being hit by the cart. Then, Goldmann meets a beggar, a supposed veteran of a battle, who tells him a story that ends up being one Goldmann had already heard, and they end up disagreeing about a point of the story, namely whether or not there is a scar on the veteran's buttocks. So, they go into a side street, where they are promptly arrested for indecent behavior. Once inside the cell, Pfitz (the beggar, and also the title of another of Crumey's books) admits that the story was told to him by his father, who he doubts was there either. Pfitz tells more stories, one about a princess who takes a lover she should not have. The lover is exiled, and she gets letters from him occasionally. The last letter is given to her by a soldier in a conquering army. As it turns out, the lover's son was the leader in this army, well after the lover has moved on to other lands. Pfitz admits to making this story up as well, and moves on to other stories. In the end, Goldmann is cleared of charges, but Pfitz is to be hanged. Goldmann agrees to pay a ransom to release Pfitz, but when he returns to his cell, the man is gone. Later, Goldmann reads a book about Count Zelneck, the man Pfitz was supposedly the servant of, and finds that Pfitz was a fictional character.

I found this book to be entertaining in a very surreal sort of way, especially the second and third stories. I wanted to keep reading, but it tended to make me dizzy with its twists, and various uncertainties as to whether the characters are real or not. It was a very curious book.