Tim Harford is the author of nine books, including The Undercover Economist and How To Make The World Add Up, which was a Sunday Times number 1 Business Book Bestseller. Tim is the writer and presenter of the Cautionary Tales podcast, starring Helena Bonham Carter and Jeffrey Wright, which has already reached 10 million downloads. He is also the presenter of the BBC Radio shows More or Less, Fifty Things That Made The Modern Economy and How To Vaccinate The World - where his guests included Anthony Fauci and Bill Gates.

Tim's TED talks have been viewed more than 11 million times and he has spoken at the Royal Institution and the Sydney Opera House. He is a member of Nuffield College, Oxford, an honorary fellow of the Royal Statistical Society, and in 2019 was made an OBE "for services to improving economic understanding".

Tim's children are aged 16, 14 and 9.

Ollie is a London-based illustrator who loves to draw playful character-led illustrations. He has worked on a variety of projects in publishing and by commission, but his favourite thing is making books for young people.