Oddly enough, the only qualification he has in computers is a rather old GCSE in Computer Science.
But he’s been messing around with computers, programming them and working out how they work since the age of 7.
More importantly, he’s also learnt the knack of explaining things simply, remembering the person he’s talking (or writing) to isn’t an expert.
That’s why his books have proven so popular.
And these tips, too.