Hold on to your hats now.

Rose Zimmer is a fine old example of what they no longer make in America: Communists. A zoftig, curvy New York girl who can never stop talking, she marries Albert, a fellow Red, in the 1940s. He is German, his Communism of the 'coffee and cake' variety; they never really see eye to eye. By the time Albert is sent by the Party back behind the East German border, he has left Rose and become a drunk. Their daughter, Miriam, comes of age in the 1960s, with all that that entails in New York: sit-ins, teach-ins, coffee houses in Greenwich Village, and so much folk music you could plotz (collapse).

Rose is the left-wing Jewish intellectual mother of all time. She and Miriam live together in Queens, memorably described by Jonathan Lethem as the "suburb of the enraged". Dissident Gardens is partly a pun on Sunnyside Gardens, a "socialist suburb", and the setting for this, the most turbulent mother/daughter battle in literary history.

Miriam is Rose's child and gives as good as she gets; eventually she decamps for Manhattan. Rose spends her working life as a bookkeeper in a radish and pickle factory. In middle age she becomes a kind of foot-soldier Communist, helping people in the neighbourhood (but excoriating them at the same time). She takes lovers, finally settling, to the dismay of everyone in her orbit, on Douglas Lookins, a Negro police officer. It is, she says, not the desire of Jew for Negro, but of Commie for cop.

Lookins's wife beomes ill, and Rose takes over part of the rearing of his son, Cicero. Miriam also takes a hand in drawing this sharp but shy suburban boy into the urbs, bringing him to meet her awful chess-whizz cousin Lenin ("Lenny"), a numismatist (the studying or collection of currency) who eventually falls under the weight of his own corruption.

Meanwhile, Miriam has a child, Sergius, with a briefly-famous Irish folk singer. Sergius is raised by Quakers, evolving into a guitar-playing Quaker himself while Cicero uses police scholarship money to become a theory-addled academic sybarite. These two are what will remain of a forceful left-wing dynasty, and the questions posed by Lethem about their future are arresting.

Miriam and the folk singer become actual revolutionaries, or at least leave the US for Central America; they are undone by high ideals (her mother's) - and not enough information.

This is a perceptive novel about ageing people, as well as ageing ideas. Rose slowly loses her marbles. She succumbs to a fantasy life involving a well-known television character - I can't bear to tell you which. "Dialectic had collapsed for Rose everywhere," Lethem tells us poignantly. As she is one of the two strongest characters in the novel, it is possible to feel a little left out of her complete biography, although this is a story of nervous, genetic movement of politics from one generation to another.

The novel employs complex flashbacks, inserting surprisingly long back-stories into some intensely present moments. It can be slippery, but once or twice it works uncommonly well. And being by Jonathan Lethem, there are observations to delight in as well as masterful linguistic play: who knew that teenagers sulking makes a sound? He describes the 1970s as a "Ponzi scheme of herpes and divorce". And as a devotee of Mad magazine, I was thrilled to see the word "fershlugginer" once again in print.

In the end we are left in the company of Sergius. He has just had sex with an unwashed Occupy girl in the toilet of a little New England airport, his head is spinning and now he is subjected to the nightmare of amateurish American airport security ("the murmur of ritual compliance"). Lethem shows him in the same light in which Rose would have seen him: swimming, like many in their twenties, in the philosophical goo of the web, the culture of hearsay. He has little with which to confront the security state but the memory of his father's protest songs and the feeble proto-rhetoric of Occupy. But there is revolution in his veins and when he is questioned, confront it he does.

This is an exciting novel to encounter at the present - when the left has never seemed so thwarted, ideologies swamped and collective action almost impossible. Three generations of this intense, lurching family - loving withal - foster and preserve the questioning, the not settling for second best, that characterises New York and the best of America.

Lethem has a great feeling for it. Is this spirit still extant? Could it "trickle down" into the students, singers and even the radish and pickle workers of today? It seems unlikely, and that is the sadness and great necessary achievement of this novel.