The following summary of results from the first 2-year closure experiment (September 26, 1991 to September 26, 1993) in Biosphere 2 is excerpted from a chapter written by William Dempster and myself for a book, Strategies for Mars, edited by Carol Stoker and Carter Emmart of NASA Ames Research Center. The book will be published later this year by Krieger Publishers. It brings together a number of the most striking initial results, including food production and nutrition; ecosystem changes; oxygen and carbon dioxide dynamics; and the human role and response to living in a small, recycling life support system. The references cited are useful as a guide to currently available articles in journals. Hopefully, the next year will see a proliferation of papers presenting more data from the first 2 years of Biosphere 2's operation. There was a wealth of data collected during the closure and by teams of researchers who had access to the facility during the 5-month transition period following the departure of the first crew and the commencement of the second closure experiment in March, 1994.