Part I: The Beginnings

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The science of human development has many beginnings; each of the first four chapters of this text forms one corner of a solid foundation for our study.

Chapter 1 introduces definitions and dimensions, explaining research strategies and methods that help us understand how people change as they age. The power of culture and context, as well as the dynamic interactions of human development, are emphasized.

Without ideas we would wonder where to start. Chapter 2 provides guideposts. Five major theories, each leading to many other theories and hypotheses, are described.

Chapter 3 explains the specifics of heredity. Genes never act alone, yet no development—whether in body or brain, at any time, in anyone—is unaffected by DNA.

Chapter 4 details the early biological growth of each developing person, from one cell to a newborn. Circumstances in embryonic and fetal growth impact the entire life span; prenatal beginnings continue to echo in the final hours.

The science and the wonder of human life begin long before the first breath. Understanding the beginnings described in each of these chapters prepares us for every later time.