This is the tenth volume of a continuing series intended to provide a forum for publication of develop­ ments in f:lossbauer Effect t1ethodology and in Spectroscopy and its applications. r~ossbauer Effect t·1ethodo 1 ogy, Vo 1 ume 1 0, records the proceedings of the Tenth Symposium on r10ssbauer Effect Hethodo 1 ogy. The Sympos i urn \'laS sponsored by the Ne~" England Nuclear Corporation, with special emphasis on applications in catalysis and in biology. The Symposium VIaS held in the t,lercury Ballroom of the New York Hilton on February 1, 1976. Dr. f,1. Good presided over the meeting. 11ore than one hundred participants were involved in the technical sessions and the exhibit of H5ssbauer effect instruments, equipment and materials by Elscint, Inc., Ranger Engineering and New England Nuclear. Continued evolution and improvement was the keynote of the ex hi bi to As has been our experience in recent Symposia, many more papers were submitted than could be accommodated. The Selection Committee was hard-pressed to limit the number of papers, and the sessions were lengthy, despite their efforts.