Andy Griffiths and Terry Denton are a creative partnership that began with Just Tricking! in 1997 and now extends to seven Just books and more than a million copies sold, the award-winning The Bad Book, the off-the-wall success of The Cat on the Mat is Flat and the bestselling The Very Bad Book. They are now published all over the world including the US where Andy's Bum books have made the New York Times bestseller lists. The hugely popular Treehouse series has blasted its way up the bestselling charts since The 13-Storey Treehouse was published in 2011.