A short series of four discussions around BIG concepts begin at Foyles (Charing Cross Road) next week. The series kicks off with perhaps THE biggest idea of the 20th Century, relativity, on 15 September. Physics authors Joseph Schwartz and Manjit Kumar will explain Einstein's most famous brainwave (or brainparticle, given duality). On 24 September, economists Peter Pugh and Tetsuya Ishikawa tackle that always topical beast, capitalism. The third in the series, on 7 October, seems something of an outlier. Focussing on an individual, Introducing Focault, with Chris Horrocks and Darian Leader feels like a welterweight of a title next to the grand concepts of other talks. But the evening will touch on issues of society, the individual, power, sexuality, madness and confinement, and promises to be just as meaty. The series concludes on 22 October when Anthony O'Hear and Julian Baggini take on one of the most ancient of human sticking points: ethics. The talks support the launch of a new set of books in the 'Introducing' series (one day there'll be an 'Introducing city-themed blogs' and we'll be up there). All talks start at 6.30 and are free to attend. You can reserve a place by emailing firstname.lastname@example.org Image / Buckaroo Kid.