The latest edition, with a knowledgeable new author team, has enlisted 21 scientists to provide revisions and content updates in their individual fields of expertise, ensuring that Lewin's GENES X is the most current and comprehensive text in the field. Informative new chapters, as well as a reorganization of material, provide a more logical flow of topics and many chapters have been renamed to better indicate their contents. Lewin's GENES X also contains new pedagogical features to help students learn as they read and an online student study guide allows students to test themselves on key material.