A marvellous book for all Electron owners is Mastering The Electron by Simon (just Simon) and John Matthews.

An introduction to BBC BASIC follows on nicely from the introductory literature you get with you micro and is packed with useful examples.

Function keys, user defined characters, colour, graphics, sound, music, the filing system and program development are just some of the topics touched upon.

Having covered BASIC so thoroughly, the authors now move onto machine code. Once again there are plenty of examples to experiment with, and lots of explanation about just what is going on amongst the silicon switches beneath the cream casing.

And if machine code isn't ambitious enough for you, there is the first chapter I have seen in any Electron book on interfacing. The authors explain address decoding, use of interrupts and go on to describe simple projects for joystick, I/O port, printer port and proportional joystick controller.

This is the best book around at the moment for Electron owners. It's published by Ellis Horwood and will cost you just £5.95.