Problems to be solved and advantages offered in the recycling of municipal solid wastes are analyzed. The development of materials recovery systems is still in an elementary stage except for ferrous metals recovery. However, only a very small fraction of municipal solid waste is subjected to any type of materials recovery. The problems to be solved in the recovery of nonferrous metals, potentially the most valuable recovered products, are summarized. Glass recovery and plastics recovery are considered. The production of fuel from municipal wastes is receiving increasing interest as one way to alleviate the oil shortages. Problems other than technical to be solved in the recycling of municipal solid wastes are indicated. (JSR)