Internet Linked Books?
New Usborne Internet-Linked Series 
What is an Usborne Internet-linked book? It is a book that contains Usborne-recommended, relevant Web sites, specially chosen by our editors land Web researchers, to take the reader further into the subject, adding new dimensions of information and entertainment. Will the Web sites go out of date? Web sites do change from time to time. The sites recommended in these books will be reviewed regularly and you will always be able to find up-to-date direct links to these or other suitable, alternative sites at www.usborne.com. Free downloadable pictures. A selection of useful diagrams and pictures from this book is available for downloading, without charge, also from www.usborne.com. Must I be online to use these books? Absolutely not. This book works perfectly well as an outstanding conventional reference book without using the Internet at all.