1. Introductory remarks (Invited discourse).- 2. A survey of instruments and experiments for X-ray astronomy (Invited discourse).- 3. General survey of X-ray sources (Invited discourse).- 4. Techniques for improving the sensitivity of proportional counters used in X-ray astronomy.- 5. Upper-air fluorescence as a tool in X-ray astronomy and searches for X-rays from NP 0532 and other pulsars.- 6. A proposal for an X-ray experiment for Cos-B.- 7. Studies of discrete cosmic X-ray sources at M.I.T. (Invited discourse).- 8. Properties of individual X-ray sources (Invited discourse).- 9. Properties of individual X-ray sources (Invited discourse).- 10. Rocket observations of Virgo XR-1.- 11. Intensities and spectra of several galactic X-ray sources.- 12. X-ray flux from discrete sources.- 13. Energy spectra of several discrete X-ray sources in the 20-120 keV range.- 14. Sudden changes in the intensity of high energy X-rays from Sco X-1.- 15. Properties of individual X-ray sources (Invited discourse).- 16. The flux of hard radiation from M87.- 17. A rocket observation of cosmic X-rays in the energy range between 0.15 and 20 keV.- 18. Angular size and position of the X-ray source Cyg-X-1.- 19. Interstellar absorption of X-rays emitted supernova remnants.- 20. The possible detection of iron line emission from Sco X-1.- 21. Hard X-rays from the southern sky.- 22. X-ray polarization from Sco X-1 and Tau X-1.- 23. Ionospheric effects of X-rays from discrete galactic sources.- 24. Non-solar Gamma and X-ray astronomy: optical observations (Invited discourse).- 25. Spectroscopic and statistical properties of X-ray sources (Invited discourse).- 26. Identification of X-ray sources at Cerro Tololo inter-American observatory.- 27. OAO observations of Sco X-1.- 28. On the magnitude-colorrelation for Cygnus X-2 and WX Centauri.- 29. On the nature of the X-ray sources Scorpio X-1 and Centaurus X-2.- 30. An X-ray pulsar in the Crab Nebula.- 31. A search for pulsed hard radiation from the Crab Nebula.- 32. X-ray pulsar in the Crab Nebula.- 33. X-ray pulsar in the Crab Nebula.- 34. A search for high-energy ?-rays from pulsars.- 35. Radio, optical and X-ray emission from pulsars.- 36. Rotating neutron stars, pulsars, and cosmic X-ray sources.- 37. Emission mechanisms in X-ray sources (Invited discourse).- 38. Theories of discrete X-ray and ?-ray sources (Invited discourse).- 39. Predicted X-ray fluxes of stellar coronas.- 40. Physical processes in Cyg X-2.- 41. The electromagnetic spectrum of the Crab Nebula.- 42. A lower limit to the magnetic field in the Crab Nebula from cosmic ?-ray experiments at 1011 eV.- 43. Some possible implications of the radio emission of Sco X-1.- 44. Observational results on diffuse cosmic X-rays (Invited discourse).- 45. Review of observational results on ?-ray background (Invited discourse).- 46. Evidence for a galactic component of the diffuse X-ray background.- 47. Observations on diffuse cosmic X-rays in the energy range 20-120 keV.- 48. Search for galactic ?-rays with energies greater than 500 MeV on board OGO-5.- 49. Spark-chamber observation of galactic ?-radiation.- 50. The low energy diffuse cosmic X-radiation.- 51. 2-20 keV X-ray sky background.- 52. ?-ray astronomy balloon results.- 53. Measurement of the cosmic X-ray background in the 25-200 keV range.- 54. Results of two balloon flights for the detection of high energy ?-rays.- 55. The cosmic ?-ray spectrum near 1 MeV observed by the ERS-18 satellite.- 56. Intensity and galactic absorption of soft back-ground X-rays.- 57. Origin of the cosmic X-raybackground (Invited discourse).- 58. Cosmic background X-rays produced by intergalactic innerbremsstrahlung.- 59. A model of ?-ray sources in the Galaxy.- 60. The X-ray emission of a hot dense intergalactic plasma.- 61. Possible initial evidence of extragalactic cosmic-ray protons and the age of extragalactic cosmic-ray sources.- 62. Galactic line emission from 1-10 keV.- 63. Diffuse cosmic X-rays from non-thermal intergalactic bremsstrahlung.- 64. Interactions of non-thermal X-rays and ultraviolet radiation with the intergalactic gas.- 65. Soft X-rays from the Galaxy.- 66. X-ray emission from the solar wind.- 67. Mechanism for X-ray production in extars.- 68. Concluding remarks.
