I am grateful to Krishnarao Appasani for making the Herculean effort to prepare this volume on the rapidly expanding fields of Genome-Wide Association Studies (GWAS) and personalized medicine, and for inviting me to offer a few of my own introductory statements.

The complexity of the human disease state has always been an area of human curiosity. Over the last decade, GWASs have enabled us to expand our understanding of complex diseases using genetic-based approaches. We now see GWAS as a technology platform that promises to help move us into the era of personalized medicine.

Genome-Wide Association Studies: From Polymorphism to Personalized Medicine edited by Dr. Appasani has assembled the contributing chapters into five main areas encompassing: an introduction to GWAS in medicine, GWAS in pharmacogenomics, different classes of genetic variants for GWAS, new technologies including next-generation sequencing, and population genetics. The component chapters will be highly valuable, not only to those who are experimentally active in these aspects of research, but also to those interested in potential drug discovery applications. The historical perspectives offered also bring forward a unique vantage point into ongoing and future research in this field.

I believe that this book will become a reliable guide for anyone attempting to understand the successes with GWAS, planning new experiments, as well as its potential for the advancement of medicine. We approach a time where advances in genome sequencing technologies will deliver the long-awaited $1,000 genome, which promises to enable capture of all classes of genetic variants in a single experiment empowering new and innovative future studies. As such, studying the content of this book will allow us to pause and reflect, of where the field has come from, and where it needs to now go.

Almost 10 years of GWAS: a feast of discoveries

Genome-wide association studies (GWASs) are less than 10 years old but have revolutionized discoveries in human genetics. GWAS is an experimental design based upon association because it exploits the fact that genetic variants that are close together tend to be statistically correlated. Driven by advances in array technologies these genome surveys of genetic variation have led to the discovery of thousands of DNA variants that are associated with complex traits, including many diseases. They have also led to new insights in human evolution and population differences.