Migration: 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 with criminal people-smuggling, Arnold conducts us on an impressively orchestrated tour of population movements all over the world: from former soviet states to Russia, between countries in south-east Asia and Africa, to and from north America, and (increasingly) from China to Africa. (The scale of internal migration within China itself  mainly from countryside to city  dwarfs all other movements between countries.) The style can be a bit imprecise and repetitive, but the accumulation of facts and statistics has its own irresistible rhetorical force.

Better than Human by Allen Buchanan (Oxford, £12.99)

People wanting to move countries are often portrayed as subhuman (as long as they are poor). If "biomedical enhancements" can make the rest of us superhuman, maybe they should get some too. Buchanan's incisive argument about improving human capacities with drugs and genetic engineering points out that enhancements are already here: healthy American students use the ADHD drug Ritalin to help them concentrate better; while search engines, coffee and even, Buchanan argues, "literacy" itself, are enhancments too.

Buchanan is no naive flag-waver for an exciting sci-fi future of upgraded humans, but he does think enhancement could be a "noble activity". (If a drug could make us more moral beings, wouldn't it be wrong not to use it?) He is good at undermining the shaky rhetoric of "playing God", and shows that fears of "altering the gene pool" rest on an unfounded assumption that evolution is already doing the best possible job. Regarding the uneven future distribution of enhancements, Buchanan worries more about "domination" by the enhanced and "exclusion" of the unenhanced than about inequality per se. One needn't agree with all of this excellent little book to find it useful: the literary equivalent of a handful of smart pills.

21st Century Dodos by Steve Stack (Friday Books, £12.99)

Remember the cassette tape, Concorde, and the ZX81? This book's "endangered list" of objects is a little incoherent since some are already vanished permanently (farewell then, Smash Hits and Look-in magazines), thus getting a five-dodo rating from the author; others are known to be on the way out (the analogue TV signal, four dodos); while yet others might be undergoing revival as we speak: eg satchels and Polaroid cameras (both three dodos), though possibly not also nuns.

Stack's brand of chummy 1970s and 80s nostalgia is amiable, and there is a lovely set-piece about dangerous childhood escapades on "slam door trains". He does, though, irritatingly use the expression "to coin a phrase" to mean exactly the opposite, ie not to mint a new expression but to reach lazily for the nearest ready-made cliché: "pirated tapes [...] were, to coin a phrase, well dodgy." I hope that practice itself dies out as soon as possible. And I do wish he hadn't mentioned the Texan bar, which had a brief comeback in 2005, because now I really want one.