Stephen Baxter's novel Coalescent explores the SF possibilities of our own evolution--and whether, like ants or naked mole rats, a human community could develop a hive mind. In modern England, George Poole learns in mid-life that he once had a twin sister, given as an infant to The Puissant Order of Holy Mary Queen of Virgins. The what? Poole tracks down what seems a perfectly respectable Rome-based organisation, not all that religious but with hints of underlying strangeness. Yet apparently they're not strangers. "They're family." Sixteen centuries before, the Roman-British girl Regina lives through the final, painful passing of Roman law and order in a Britain increasingly ravaged by Saxon invasion. It's a grimly moving historical story, which even links to the legend of Arthur. Hardened by much brutal experience, Regina is determined to protect her bloodline and her household gods through the Dark Ages, until this temporary disturbance is over. By luck, cunning and sheer ruthlessness she reaches sanctuary in Rome, where she founds an enclave that will survive into the modern era and beyond. Instinctively, Regina lays down rules that will fundamentally change "human nature" as the centuries slip by: Ignorance is strength. Listen to your sisters. Sisters matter more than laughters. A third narrative strand follows Lucia, a girl of the modern-day Order who sees these slogans on every wall, lives underground in the artificial light of the "Crypt" and is always surrounded by many sisters. No room is ever empty. When Lucia finds herself physically changing and becoming different from her workmates, the resulting upheaval has ripples that affect Poole, his own rediscovered sister and the world. The lifestyle of the Order is a new quirk in mankind's evolution, alternately seductive and shocking. Baxter switches effectively between harrowing historical narrative and the slow revelation of a threat whose understated chill is reminiscent of John Wyndham's quieter menaces. Coalescent is a strong, standalone novel that opens a new SF sequence titled "Destiny's Children". --David Langford