« This book has two basic aims. First, to provide ZX81 and ZX Spectrum owners with a source of ‘off the peg’ programs which do real computing work in a wide field of applications. Second, to give the reader an insight into and an understanding of the techniques on which the software is built. To this end, full documentation and detailed commentary is provided.The ZX computers have enormous potential that is often unexploited. This potential can be realised if programs for the ZX81 and Spectrum are made to be as good as software written for other machines. The ‘building­ block’ approach described by the author will enable readers to utilise the ZX machines’ capabilities more fully and to facilitate and speed up the production of high quality software of their own. »