Migration: Changing the World by Guy Arnold, Better than Human by Allen Buchanan and 21st Century Dodos by Steve StackMigration: Changing the World by Guy Arnold (Pluto Press, £19.99)Migration has always happened, and it is almost always good for the destination country. Migrants go where the jobs are, rather than "stealing" jobs from the locals, and they contribute to economic growth in developed countries whose populations would otherwise shrink. So runs the repeated lesson of this dense but illuminating study, whose author's sympathies are clear: "Globalisation [...] must also mean the globalisation of people."Drily demolishing the xenophobic assumptions behind the desire to maintain a "fortress Europe" that will not be "swamped" by aliens, and the pernicious conflation of voluntary migration ...