The return of the forum for wry investigation of life's unanswerables, based on the weekly question-and-answer feature in The Guardian. This week: what is happiness, why do crabs walk sideways, and is there such a thing as the perfect crime? Guests include Richard O'Brien ,
Nigel Dempster and P D James. Also featuring Carol Vorderman. Producer Philippe Bassett Series editor Leela Creswell
A Celandine production for BBCtv SEE THIS WEEK page 17