Letter from Thomas Gold to Dr Donald Clayton, Department of Space Physics and Astronomy, Rice University, Houston, Texas Gives his response to the questionnaire. The item he would most like to hear discussed is the question whether a single nucleogenetic mix is responsible for the entire solar system. Gold would be willing to summarise the solar system problem that should cause one to look at all the data once more. Someone else should discuss the isotope evidence (Allende, etc) to date. Gold thinks he can make a very strong case against the surface enrichment of the Moon and the Earth having come from a differentiation process on these bodies, though that by itself need mean no more that a sorting process had occurred somewhere else. It opens up a major question once more. 5 May 1976