Joseph and Frank Leyendecker were both included in an early instalment of the unsung heroes series. But I realise they are far too important in the development of 20th century illustration to be summed up so briefly. So this is a more detailed look at the work of both of these remarkably talented and influential figures, which I've attempted to create as a joint profile in order to compare and contrast their skills and output. It seems I've also made an unfortunate typographic error and had them both born in the 1970s. What can I say? I'm overworked and underpaid.