Dear Undercover Economist by Tim Harford Abacus, HK$136 In response to the question 'how many children should we have?' Tim Harford, The Undercover Economist, says it's wrong to think quantity without quality, then cites Malthus (who mistakenly predicted that when household incomes rise, families expand to consume new resources). To a woman who enjoys dating but worries she might be leaving it too late to settle down he brings up optimal experimentation theory. This is an Agony Aunt collection with a difference; the person dishing out the advice is doing so through the lens of an economist. That's why Harford, a Financial Times columnist, sacrifices specifics for one-size-fits-all theories for everything from parenting to etiquette to sex. In his Food, Drink and Entertainment section, to the bleat about having to share food at restaurants when eating with friends, Harford explains the Coase theorem, which 'predicts a happy outcome if property rights are clearly specified'. It means telling your mates you hold ownership rights to your dish. Harford's ability to make economic theory relevant to everyday life easily understood and humorous are skills of which he can proud.