Book excerpt: Outlining the most important concepts of clinical embryology, the second edition of this full color atlas gives a well-illustrated overview of human development before birth. Each chapter has been thoroughly revised with the most up-to-date information. Accompanied by authoritative descriptions, this superb resource provides a step-by-step review of normal and abnormal embryonic and fetal development through hundreds of color photographs, 3-dimensional drawings, electron micrographs, sonograms, MR images, and pen-and-ink sketches. It also includes photographs and tables indicating periods when tissue and organ formations may be affected by teratogenic agents.