CONTENTS
1. Introduction 198
2. General Pattern of Twilight Phenomena 200
3. Spectrophotometry of the Twilight Sky 202
4. Polarimetry of the Twilight Sky 211
5. Geometry of Sun's Rays and Their Attenuation on Their Path Through the Atmosphere 215
6. Twilight Illumination of the Atmosphere 220
7. Brightness of the Twilight Sky. The Twilight Layer 223
8. Effective Boundary of the Earth's Shadow and its Dependence on the Structure of the Atmosphere. Phases of Twilight 226
9. Color of the Twilight Sky 230
10. The Problem of Multiple Scattering. Deep Twilight and the Transition into Night 234
11. The Inverse Problem of Twilight Theory and Twilight Sounding of the Atmosphere 239
12. Differential Method of Solving the Inverse Problem and the Method of Effective Height of the Earth's Shadow 242
Literature 246