Tohby was born and raised in Sydney and has a BA in Visual Arts and a BSc (Architecture) although he has spent his post-graduate years doing anything but architecture - with great success. Tohby Riddle is an illustrator and writer whose deceptively simple illustrations contain the most fascinating detail. His picture books charm children and all lovers of illustration.

Since 1989 he has been accountable for a number of picture books that have been published in Australia, the United Kingdom and the United States. One book, The Great Escape from City Zoo, has had the feature film rights to it bought by a Hollywood studio.

As well as creating picture books, Tohby contributes cartoons to a number of publications and is regularly featured in the Sydney Morning Herald's Good Weekend Magazine. The popularity of Tohby's cartoons has lead to the 2003 release of a collection of his work entitled The Big Idea. 

Tohby has also visited schools, universities and writers' festivals across Australia to talk about his work and other things that come to mind, and has spent a number of years as an editor.