1. Early Functional and Structural Development of the Nonhuman Auditory System 2. Early Development of the Human Auditory System and Its Relationship to Nonhuman Auditory Development 3. Absolute Sensitivity 4. Factors Related to Thresholds in Noise: Intensity, Frequency, and Temporal Resolution 5. Other Response Properties: Development of Complex Sound Perception and Binaural Hearing 6. Effects of Experience 7. Epilogue