This text offers a fresh, distinctive approach to the teaching of molecular biology that reflects the challenge of teaching a subject that is in many ways unrecognizable from the molecular biology of the 20th century - a discipline in which our understanding has advanced immeasurably, but about which many questions remain to be answered. With a focus on key principles, this text emphasizes the commonalities that exist between the three kingdoms of life, giving students an accurate depiction of our current understanding of the nature of molecular biology and the differences that underpin biological diversity.