This book is to serve as a textbook to introduce the statistical principles and methods in mapping disease genes to students and researchers with a basic statistical background. The book will emphasize the principles and ideas, illustrated with examples in the text. In addition, it has a good number of exercises, both for the students to practice the statistical tools they have learned and also to point to research topice that have been covered in the literature. Furthermore, relevant computer programs will be discussed at the end of each chapter and sample codes will be provided at a book web site.