As important and inspirational as modern biology is, these are also the most challenging times to teach and learn the subject. In the era of ever-expanding biology, we have no choice but to make our course less encyclopedic. Leading the way in this movement are the many thoughtful instructors who have opted to cover fewer main biology topics rather than compromise depth in the most importment areas. To support this trend, we focused on four core topics: cell, genes, evolution, and ecology. By exploring these four areas and fitting them together, students can synthesize a coherent view of life. In the context of these four main topics,students will encounter diverse organisms and their evolutionary adaptations. However, we have not included separate units on the anatomy and physiology of plants,animals,and other organisms. This enable us to keep Essential Biology manageable in size—and,well,essential—without being superficial in the areas we chose to cover. We take the “less is more”mantra in education today to mean fewer topics,not more dilute explanations. Even with a decision to cover fewer major topics,there is still the potential for biology to collapse into a formless pile of terms and factoids. An integrated view of life depends on a theme that cuts across all topics. We named our course Essential Biology partly because this course at life is relatively brief,selective,and integrated. But the title has a second meaning. It announces an emphasis on concepts and applications that are essential for students to make biologically informed decisions throughout their lives—to evaluate certain health and environmental issues,for example. Biology is more essential than ever in a general education,and we’ve tried to spotlight this central place of biology in modern culture.