Section I. History and special events.- Inroduction.- A Historical Introduction to the Search for Extraterrestrial Life.- Twenty-Five Years of the Search for Extraterrestrial Communications.- SETI is Coming of Age.- Welcoming Address.- Invocation.- Section II. The Search for Other Planetary Systems.- A Review of the Scientific Rationale and Methods Used in the Search for Other Planetary Systems.- Protoplanetary Material Around Nearby Stars.- On the Number of Galactic Planetary Systems.- Planetary Searches Using Optical Astrometric Interferometers.- A New Objective for the Allegheny Observatory 30-Inch Refractor.- Prospects for Space Telescope in the Search for Other Planetary Systems.- Detecting Distant Planets with Space Telescope.- Absolute Astronomical Accelerometry: A New Tool for Planetary Searching.- Assisting Extrasolar Planetary Detection through the Determination of Stellar Space Orientations.- Section III. Planetary, Interplanetary and Interstellar Organic Matter.- Titan’s Organic Chemistry.- Prebiotic Matter in Interstellar Molecules.- Recent Observations of Organic Molecules in Nearby Cold, Dark Interstellar Clouds.- Infrared Spectral Identification of Complex Organic Molecules in Interstellar Grains.- Universal Protein Ancestors from Hydrogen Cyanide and Water.- Panspermia — A Modern Astrophysical and Biological Approach.- No Valid Evidence Exists for Interstellar Proteins, Bacteria, Etc,.- Astronomical Sources of Circularly Polarized Light and their Role in Determining Molecular Chirality on Earth.- Section IV. Universal Aspects of Biological Evolution.- Synthesis and Analysis in Chemical Evolution.- Molecular Replication.- The Precambrian Evolution of Terrestrial Life.- Human Evolution: The View from Saturn.- Some Implications of Mass Extinction for the Evolution of Complex Life.- Evidence for a Solar Companion Star.- The Universal Diagrams and Life in the Universe.- Universal Aspects of Biological Evolution.- On the Occurrence and Appearance of Galactic Life Forms: A Thermodynamic Approach.- Section V. Radio Searches — Recent Observations.- SETI Observations Worldwide.- Project Sentinel: Ultra-Narrowband SETI at Harvard/Smithsonian.- The Ohio SETI Program — The First Decade.- A Search in the Infrared to Microwave for Astroengineering Activity.- Search for Strongly Polarized Radio Emission from E.T.I., and an Optimist Approach to the Great Silence (Fermi’s Paradox).- Lunar Reflections of Terrestrial Radio Leakage.- Eavesdropping Detection of Radio Signals from other Planets with one Bit Implementation Techniques Using Existing Computers.- Section VI. Technological Progress in Radio Searches.- Seti: A More Eclectic Approach.- The 8-Million Channel Narrowband Analyzer.- The Multichannel Spectrum Analyzer.- Software Implementation of Detection Algorithms for the MCSA.- Seti: The Microwave Search Problem and the Targeted Search Approach.- Seti: The Microwave Search Problem and the NASA Sky Survey Approach.- An Analysis of the Elements of an All Sky Survey.- Optimum Search Strategy for Randomly Distributed CW Transmitters.- A Milky Way Search Strategy for Extraterrestrial Intelligence.- The Serendip II Design.- New 45m Radio Telescope and Fourier-Transform Type Spectrometer at Nobeyama Radio Observatory.- Section VII. The Fermi Paradox and Alternative Search Strategies.- A Comparative Analysis of Space Colonization Enterprises.- On The Question of Interstellar Travel.- Exponential Expansion: Galactic Destiny or Technological Hubris?.- Where Are They? Implications of Ancient and Future Migrations.- Galactic Colonization and Competition in a Young Galactic Disk.- Extraterrestrial Intelligence: Where is Everybody?.- Fermi Question, Fermi Paradox: One Hit, One Out.- On a Cosmic Alphabet.- On the Inevitability and the Possible Structures of Supercivilizations.- An Infrared Search in our Solar System as Part of a More Flexible Search Strategy.- Section VIII. Summaries, Comments and Conclusions.- Summary of Session I. The Search for Planets Around other Stars.- Summary of Session II. Planetary, Interplanetary and Interstellar Organic Matter.- Summary of Session III. Universal Aspects of Biological Evolution.- Questionmarks Remaining.- Two Additional Comments.- A Look into the Future.- Concluding Remarks.- Activities and Resolutions of IAU Commission 51.- Epilogue.