Thermodynamics is one of those words best avoided in a book with any pretence to be popular, but it is more engaging if seen for what it is: the science of 'desire'. The existence of atoms and molecules is dominated by 'attractions', 'repulsions', 'wants' and 'discharges', to the point that it becomes virtually impossible to write about chemistry without giving in to some sort of randy anthromorphism. Molecules 'want' to lose or gain electrons; attract opposite charges; repulse similar charges; or cohabit with molecules of similar character. A chemical reaction happens spontaneously if all the molecular partners desire to participate; or they can be pressed to react unwillingly through greater force. And of course some molecules really want to react but find it hard to overcome their innate shyness. A little gentle flirtation might prompt a massive release of lust, a discharge of pure energy. But perhaps I should stop there.