1. Observation of X-ray sources outside the solar system

   • Riccardo Giacconi
   • Herbert Gursky

   OriginalPaper Pages: 151 - 175

2. Airglow

   • V. I. Krasovskij
   • N. N. Šefov

   OriginalPaper Pages: 176 - 198

3. Effects of electromagnetic perturbations on particles trapped in the radiation belts

   • J. W. Dungey

   OriginalPaper Pages: 199 - 222

4. Theory of movement of irregularities in the ionosphere

   • S. Kato

   OriginalPaper Pages: 223 - 235

5. The stellar triangulation with photographic observations

   • A. J. Corpacius

   OriginalPaper Pages: 236 - 261

6. Book reviews

   • C. de J.

   BookReview Pages: 262 - 262