Andrew Dickens, one of the three authors of the Advanced User Guide for the BBC Micro (Bray, Dickens and Holmes) which was required reading for serious programming. It includes machine code basics, 6502 assembly, OS calls, full circuit diagram, addresses and registers of all the I/O chips.

From this short posting: http://www.acornarcade.com/forums/viewthread.php?threadid=11272 we get to this article about Andrew: http://www.cambridgenetwork.co.uk/news/article/?objid=14496 and some detail about his company which still seems to be doing well, funded initially from sales of that book, written when he was at college with two collaborators.

http://www.adder.com/about

From the article:

Mr Dickens, a fresh-faced fortysomething, is the founder and chief executive of Adder Technology, a company at the forefront in its field, and yet as traditional as Dombey & Son in its structure and funding. 'The long-term goal is to grow the business into a much bigger company, not to sell it.' An unusual ambition for a Cambridge high tech company, with most leaving room on the brass plaque for 'Inc'. Adder - turnover 6m, in profit for 22 years, current growth rate 50% per annum - is best known in the sector for its KVM (keyboard, video, mouse) switches and extenders. Actually, it's a world leader at the top end of the market. It has always been profitable, has enjoyed a smooth path, but has recently embarked on something much more risky - a chip business, Adventiq, which has been formed with Cambridge-based RealVNC, and is being led by the charismatic Peter Wharton, until very recently ceo of Cambridge Broadband. But, back to books. The young Adrian, born in Oxford, brought up in Leicester, a grammar school boy, arrived in Cambridge in 1981 - Churchill College, engineering.