This book Provides a thorough overview of development in data mining tools is to effectively and efficiently extract useful biological information from gene expression datasets in pattern-recognition to allow the development of clustering and classification techniques. Discuss the incorporated computational models to extract hidden and useful information and illustrates the concepts of feature selection, clustering and classification techniques. This book will maintain and generate an interest in data mining methods. It major findings of this book in detail as follows: complete information on gene clustering, classification of basic concepts in data mining, expanded explanation of hybrid pattern discovery techniques, stating and development of new algorithmic approaches step by step .