"Mara and Dann," this tale's haunting predecessor (and, I think, one of Lessing's most powerful and imaginative and accessible books), followed its brother-and-sister heroes as they traversed the African continent at the end of an Ice Age many millennia in the future. Their harrowing adventures brought them to a farm within walking distance of the Rocky Gates (Straits of Gibraltar), the Western Sea (Atlantic), and the rapidly filling cavernous expanse of the Middle Sea (Mediterranean).
The sequel begins nine months later, when Dann decides to fulfill his dream of exploring the Middle Sea to see for himself the ice-covered continent of Europe and ultimately to confront the demons that assailed him during his trek through the desert. The subsequent narrative expands upon two subjects from the first book: the lust for knowledge that fueled Mara and Dann's transcontinental journey and the drug-stimulated schizophrenia that inexorably worsens Dann's ability to lead, as a reluctant "general," the refugees who make up his slapdash army. During Dann's period of incapacity, the task of running the army devolves to a sidekick named Griot; like many messianic figures, Dann requires a loyal administrator to smooth over the public perception of his bipolar outbursts.
Although "The Story of General Dann" will make little sense if you haven't read the earlier book, as a sequel it is both satisfying (tying up loose ends and expanding on earlier themes) and frustrating (leaving just as many loose ends). The book's pacing is admittedly slower and the plot is slighter: this is more a character study than an adventure story. Significant portions of the book deal with Dann's psychological breakdowns, with Griot's hunger for Dann's approval, and with their obsession with finding out as much as they can about the mysteries of the past. This sequel seems, in fact, to be a bridge to a yet-to-be-published finale.
Yet Lessing still conveys her preoccupations with the frailty of knowledge and our continual need to recreate the discoveries of the past: "it's likes seeing the worlds of ghosts.... We are looking at words that were copied from others, written by people who lived long before them." In an interview with John Freeman, Lessing spoke about this theme: "What pains me is that everything the human race has created has happened in the last 10,000 years, you know, and most of it in the recent years. An ice age would just wipe that out. It would. Then we have to begin again then, don't we, which is what we always do." The Mara and Dann books, then, are not simply disturbing fantasies disguised as adventures stories, but parables on the tenuousness and persistence of human civilization.