Karp continues to help biologists make important connections between key concepts and experimentation. The sixth edition explores core concepts in considerable depth and presents experimental detail when it helps to explain and reinforce the concepts. The majority of discussions have been modified to reflect the latest changes in the field. The book also builds on its strong illustration program by opening each chapter with 'VIP' art that serves as a visual summary for the chapter. Over 60 new micrographs and computer-derived images have been added to enhance the material. Biologists benefit from these changes as they build their skills in making the connection.