Beginning in 1950 the National Association for Research in Science Teaching and the U.S. Office of Education collaborated in preparing an annual summary of research in the teaching of science. The present bulletin continues their cooperative effort. This analysis of research in the teaching of science contains reports of published studies resulting from a meticulous search of the pamphlet and periodical literature in the field between July 1955 and July 1956. It also contains reports of unpublished studies coming from the returns to an inquiry sheet mailed annually by the U.S. Office of Education to more than 1,200 institutions where graduate work in science teaching is in progress. The studies reported here have been carefully evaluated and selected through applying a set of criteria formulated by the National Association for Research in Science Teaching. The work was carried on by three committees, one for each school level: elementary, secondary, and college. The three committees reviewed all the issues between July 1955 and July 1956 of about 50 monthly magazines which, from time to time, carried research in science teaching. The work was limited by the fact that, in both the published and unpublished studies the committees, for the most part, were working with secondary sources, such as abstracts and articles, and not with the original documents. In the preparation of this report the research for the past decade has also been reviewed in an attempt to discern any trends or patterns. At this time now, when science and technology are playing a very important part in our life and culture, much of the research in science education lacks a broad and comprehensive plan. A considerable amount is unpatterned, makes but a fragmentary contribution to the basic concerns, and tends to deal with peripheral fringes of the major problems. Nevertheless, there is some evidence of progress towards a more patterned research program. Elementary school, secondary school, and college level bibliographies are included. (Contains 2 footnotes.) [Best copy available has been provided.]