Research is limited by the instruments that it uses: from the telescope came the solar system: from the microscope came the germ theory. A subtext of these discoveries is “seeing is believing”. For all too long, psychiatric illness has been defined by what could not be seen: a lesion on autopy transformed a psychiatric disorder into a neurologic disorder. The ken of clinical responsibility of psychiatry has, therefore, been delimited to conditions with behavioral and intrapsychic symptoms without visible neuropathology. This situation, of course, has been fertile ground for the persistence of stigma, as psychiatric disorder was equated with moral weakness among the lay public and derided as “functional” by nonpsychiatric clinicians.

Fortunately, the solution for this seeming oxymoron, mental illness, came from technology. Since the mid-1980s increasingly powerful devices have been developed to image the structure, function, neurophysiology, and chemical composition of the living human brain. The impact of these technologies has been informative for brain science but transformative for psychiatry. For example, no longer can schizophrenia be considered a political act or psychologic deviance when one can see the atrophic cortex, hypofunctional frontal lobe, enhanced release of striatal dopamine and reduced levels of N-acetylaspartate.

Functional Neuroimaging in Child Psychiatry, edited by Monique Ernst and Judy Rumsey, takes current imaging opportunities and discusses their applicability to the realm of the child and adolescent subject. The power of this important textbook is that it addresses the critical fact that children are not simply miniature adults.

Critical to the application of these exciting technologies within child psychiatry are ethical considerations. Ethics is central to all research, but special issues arise when dealing with subjects who are particularly vulnerable by virtue of their age and dependence, as well as by virtue of impairments resulting from psychiatric disorders. In this section, Arnold and colleagues outline the guiding ethical principles in research with children and address the challenges specific to functional neuroimaging studies of both normal control children and those with psychiatric disorders. Specific risks imposed by functional neuroimaging and informed consent/assent issues are examined, and methods for minimizing such risks are described.

Neuroimaging studies of children, whether cross-sectional or longitudinal, are developmental in nature. This aspect requires the careful consideration and evaluation of maturational changes over time. In addition, the basis for understanding aberrant brain development rests with an understanding of normal maturation. Consequently, this section outlines brain and cognitive development and critically discusses the use of cognitive and behavioral probes in developmental imaging studies. Casanova and his colleagues provide a thoughtful and thorough review of brain development from the level of the cell to the level of gross functional anatomy and discuss the impact of genes and environment on brain organization and its evolution (Chapter 7). Pascualvaca and Morote provide an overview of the developmental trajectories of specific cognitive and neuropsychological functions (Chapter 8). Casey and her colleagues address the important themes of ageappropriate tasks for use in functional neuroimaging studies of children, illustrating these themes with paradigms used to explore prefrontal cortical functioning (Chapter 9). Together, these chapters provide an overview of brain development and cognitive development and illustrate how the two come together in study designs appropriate for mapping human brain functional development.