Following a popular trend, Rogers's latest (after Her Living Image, 1986, etc.) fuses the past and the present, reaching from the 18th-century founding of a British colony in Australia to a failing 20th-century English marriage, and conjoining the roles of two idealists, each disillusioned in his own time and place. When William Dawes lands in Australia as a young lieutenant in the British colonial force, he aims only to set up an observatory and carry out his assigned astronomer's duties. The difficulties of taming the wilderness and overseeing the cargo of convicts who are the first colonists, however, soon have him otherwise employed, and only in his spare time does he pursue his dream. His latter-day chronicler, Stephen Beech, similarly taxed by pursuing an idealistic mission in education amid the harsh realities of the British school system, has retreated to his research and writing. William's drive gets the observatory built, but his principles set him up for a series of falls, first with a female convict he befriends, then with another convict he has protected, only to have the man deliberately infect the natives with smallpox, to catastrophic effect. Finally, forced to go on a hunt for innocent natives who will be killed in retribution for the murder of a pederast who'd been in the favor of the colony's governor, William decides he's had enough and heads home. Stephen, having chosen a working-class wife and tried to be her Pygmalion, with her resentment and a deformed infant the only results, eventually packs it in too, going off to Australia in search of his subject--and himself. Ambitious and solidly researched, but the different centuries and their challenges remain largely in separate orbits, with only a huge effort at contrivance pulling them parallel, and then only briefly.