Child and Adolescent Psychopathology, Second Edition is the only comprehensive text on childhood and adolescent disorders that addresses genetic, neurobiological, and environmental factors within a developmental perspective. The new edition includes more on epigenetics, classification, culture and context and emphasizes how, when, and why disorders emerge among young people and in what ways symptom profiles change at different stages of development.
I used this textbook for my graduate-level child psychopathology class and I really liked it (and the students didn't complain about it, which is a 'win' in my book). It had a nice introduction to developmental psychopathology, did a good job going over the risk factors for psychopathology, and had clear, concise chapters for each of the major childhood disorders. I'll use it again next time I teach this class. The only drawback for me was that it came out in early 2013 so the various authors were only able to speculate about DSM-5 changes/additions/updates.