This book is about the principles of human molecular genetics. Whether you are a student or a researcher, you will also need access to genetic data – to find where a gene maps, whether the gene has been cloned, what mutations have been found, what genes are contained in a particular chromosomal region, where and when a gene is expressed during embryonic development, etc. You need the most up-to-date information, and you usually need it quickly. The place to find all such genetic data is on the Internet.The Internet is a world-wide system that links innumerable individual computers and local networks in universities, research laboratories and commercial and government organizations. It allows almost instant communication between computers anywhere in the world. All students of human molecular genetics should be using the Internet.