Rainy Brain, Sunny Brain by Elaine Fox (Heinemann, £12.99)
Do you find your brain functions less well during a miserable wet summer? Me too, but the weather in this book's title is more metaphorical. The psychologist author collates research and anecdotes about the personality traits of optimism (sunny) and pessimism (rainy). Pessimism, she argues, comes from an overactive amygdala, the "fear brain"; optimism might be self-deluding, but it's evolutionarily "highly adaptive", and tends to make good things happen. As Franklin D Roosevelt didn't quite put it: "The ultimate obstacle to an optimistic life is fear itself, our emergency brain."

Fox constructs an elegant narrative from neuroimaging results, her clever psychology experiments, and the interaction of genetics and environment. One can even learn, she promises, to be less pessimistic, with a dash of CBT, "cognitive bias modification", or meditation: so this falls into the well-populated genre of scientifically approved Stoicism. Heartwarmingly, it even seems that optimism can bring riches: Fox tells an anecdote of two Irish brothers, one of whom (the optimist) is now "a multimillionaire", and the other (less "sunny") "a schoolteacher in Dublin, struggling to pay his mortgage". What an idiot. But if everyone becomes an entrepreneur, who will educate the kids?

Why the Olympics Aren't Good for Us, and How They Can Be by Mark Perryman (OR Books, £8)
This educator, a research fellow in sport and leisure culture, also enjoys the inestimable advantage of clairvoyance. In a book published before the London Olympics, he announces that his "scepticism" about whether they would be any good for the country "turned out to be well-founded". Since I cannot claim similar powers of prediction, I will not argue. (Except to say: David Beckham on a speedboat. Come on! How is that not good for the country?)

Perryman reminds us that the torch procession was invented by the Nazis (sigh), but also mounts a detailed and persuasive case against the commercialisation of global megasport. The second half details his own, nicely quirky proposals for making a better Olympic Games. There should be more events that are free to watch and more that are cheap to train in, he argues persuasively. Why not make darts an Olympic sport? Good idea, and let's not stop there: I also nominate skipping, stickfighting and thumb war.

God: All That Matters by Mark Vernon (Hodder, £7.99)
This entry in a confidently subtitled new series of short introductions is a light-footed scoot through theologies both ancient and (post)modern. Vernon, a philosopher and former priest, likes to demonstrate Greek sources of Christian ideas (Plotinus and Plato figure heavily), and to confound the Dawkinsites with ideas of God that do not conflict with science.

Combining a gentle scepticism with sympathy for theological yearnings, the author touches on those modern-science-approved Stoics, Spinoza, William James, Don Cupitt, "process theology", game theory, the techno-eschatology of the "singularity", and "apophatic theology", which says you can't talk about God at all  in our day, Vernon comments wryly, "such theology has, arguably, become unfashionable and even a source of annoyance". Particularly interesting is his chapter on the resurgence of Taoism in China, and its potential as an "ecotheology". This is a pleasingly ecumenical exercise, with an appendix on "10 films to see" that recommends The Lord of the Rings trilogy and The Exorcist: good, perhaps, for giving your amygdala an Olympic workout and hoping it falls asleep from exhaustion.