Error coding is a fascinating subject as much, if not more so, as it is an indispensable part of modem engineering systems. Unfortunately, in a bid to remain general and to create a solid foundation upon which to build, many books on this subject are out of the reach of those with more engineering-based, or non-mathematical backgrounds. This is a pity because in many cases the maths is tractable with few and simple rules. If we are content to believe that it works, and let others worry about the deeper mysteries of how or why, then with a little practice the design and implementation of practical error coding systems becomes straightforward. In this text I have attempted to reveal the useful kernel of the subject, removing the shell of terms and proofs that usually surrounds it. Being somewhat empirical in nature ( an empiricist), and occasionally heard to quote the adage, 'if it works twice it's a law', my explanations take this form. For many, including myself, abstract ideas are often better grasped by practical illustration than from yards of theory.