Dave buries the book, which is discovered centuries later and used as the sacred text for a dogmatic, cruel, and misogynistic religion that takes hold in the remnants of southern England and London following catastrophic flooding.

Spellings are phonetic and can be opaque, making the book particularly difficult for those unfamiliar with the speech of England and London: "bugsbunny" for rabbit is easy enough, but "beefansemis" for an architectural style is less clear—it presumably comes from "[Eliza]bethan semi[-detached house]s." A glossary[1] is provided.

The book resembles, in part, Riddley Walker, a 1981 novel by Russell Hoban[2] written in a similar phonetic manner and also set in England centuries after a major disaster.

[4] At the same time, reports of increased raisings of the Thames Barrier had led him to contemplate that a catastrophic flood of London would render even detailed archival knowledge unable to reconstruct the metropolis.

For example, the "Hamsters", the inhabitants of the island of Ham (actually the higher, unflooded part of Hampstead Heath), believe that certain verses out of the book are sacred "hymns", where in fact they are just excerpts from The Knowledge.

Despite discovering that Carl is actually Cal's son, Dave slowly recovers his sanity and, during a stay in hospital, forms a relationship with Phyllis Vance, the mother of Steve, another patient.

Dave moves into Phyllis's cottage on the fringes of outer London and, under her guidance, writes a second book that repudiates the content of the first, and recommends a life based on tolerance and freedom.

The community lives according to the severely enforced religion of the country known as "Ing" (i.e. England) whereby men and women lead separate lives but share childcare in accordance with the dictates of the Book of Dave, which is regarded as a sacred text, but which is evidently the book written by Dave Rudman and buried in a Hampstead garden some two thousand years earlier.

A young male 'Hamster', Symun Devush, explores a forbidden area of the island and emerges claiming that he has discovered a second Book of Dave that repudiates the tenets of the first.