Since Kjartan got his engineering degree he has worked on children's tv (dating back to BBC's
Swap Shop!), presented science and maths programmes, warmed up thousands of studio audiences, toured his one man show, played a lot of pub pianos very loudly and has been Widow Twankey. In the last 10 years he has appeared all over the country as well as on tv demonstrating mathematical tricks and oddities from his books.
He has written many shows and pantomimes, twice winning the London Fringe Award for Best Production. He has five shows published including his world-wide musical success HENRY THE TUDOR DUDE (produced over 120 times).

His books have been translated into over 25 languages and include the "Murderous Maths" series which is all being re-issued with brand-new covers. His other
non-fiction titles include "The Gobsmacking Galaxy", "Isaac Newton and his Apple", the "Warp Maze" with cartoonist Stephen Appleby, 4 books in his notorious "Killer Puzzles" series, handbooks on Practical Jokes and Secret Codes, 4 "Rosie and Jim" annuals, 6 support books for the BBC Schools series "Megamaths",a GCSE maths guide and a book of conjuring tricks: "The Magic of Pants". He was a judge for the 2007 Blue Peter book competition.

In recent years has also written the novels "Urgum The Axeman", "Urgum and the Seat of Flames" and "Urgum and the Googoobah" which was shortlisted for the first Roald Dahl Funny prize in 2008.

He has also written songs and scripts and worked as a games consultant for a wide range of children's t.v. shows including CBBC's new TRONJI series and his music
for t.v. includes the original themes for the BBC's "BRUM" and the long running "SMART" series.

He has written for "Rosie and Jim" comic, "The Beano" and the "The Oldie" and "Mad Maths" magazine.

Currently he is finishing the big new colour "Murderous Maths of Everything" and also an adult numberacy book, he's planning more novels and adapting the Horrible Science books into stage show which will tour the UK in 2010...

...and frankly this petty list of his dismal achievements goes on forever so that'll have to do. He's married to Bridget, they have four girls and his mentionable hobbies
include running his websites, astronomy, magic tricks, making strange noises on his moog sythesisers and mending his old pinball table.