Islands: A Trip through Space and Time, by Peter Conrad; Thames & Hudson, 2009, 192 pages, $45. Islands are philosophically odd things: they were central to Locke’s bold moves against feudal tenure rights in the eighteenth century which made property transferable from the physical effort put into finding, cultivating and ultimately consuming its produce. Islands are more easily marked by such activities: that is why Shakespeare sets Prospero on one, and Defoe has Robinson Crusoe take possession of his. Islands were a new standard of independence in laying claim to the biggest parcel of land of all, the United States,…