This book contains written versions of the material presented during an intensive workshop on the topic: `Nuclei of Normal Galaxies: Lessons from the Galactic Center'. These contributions summarize the present knowledge of the conditions in our own galactic nucleus and how these extend to moderately active nuclei in external galaxies. The authors are among the foremost researchers in the field, with specialties ranging from theory to observations at gamma-ray through radio wavelengths. Fifty-five articles cover high-energy processes, gas and stellar dynamics, the structure and energetics of the Galactic center, nuclear stellar clusters, and central black holes, at a level suitable for practicing astronomers and graduate students.