Although the articles in this issue were submitted and reviewed separately, we have grouped them together because they address important common themes. The articles contribute to our understanding of relationships among the cultures of science and engineering communities, practices in science classrooms, and the diverse life histories of science learners. The informants in these studies range from elementary school children to minority women who have successfully completed college and have begun engineering careers. These learners are constantly reshaping their perceptions of scientific work and their feelings about the "fit" of science with their own lives and values.
Three of the articles focus on women in college or in professional careers. They help us understand how women in science must struggle with the cultures and practices of science and engineering communities. We can admire the determination and resourcefulness of the young women engineers portrayed by Chinn at the same time as we can see how difficult it will be for others to emulate their success. How many young minority women are likely to marshal the personal resources and the steadiness of purpose that these women have shown? Nauta and Cronin and Roger also address barriers encountered by women who are potential scientists or engineers. These barriers rarely take the form of overt discrimination, and they are not impermeable. Their effect, however, is to greatly reduce number of minorities and women who enter science and engineering careers. Furthermore, as the response to Cronin and Roger's report indicates, attempts to remove these barriers will threaten strongly held values which are the foundation of scientific and engineering communities.
The other three articles in this collection inform us about how younger learners encounter scientific values and practices. Like Chinn, Richmond and Kurth tell success stories that raise questions about how we can replicate our successes on a larger scale. Their high school informants' experiences in the laboratories of scientific mentors left them with a sense of the excitement and appeal of science as a human enterprise that they had not gotten from their experiences in science classrooms. Hanrahan reports on affirmational dialogue journals as a strategy for humanizing science classes for alienated middle school students. Andre, Whigham, Hendrickson, and Chambers report evidence that even children in early primary grades are beginning to form gender-based stereotypes of science and scientists.
"Bridging the gap" between learners and scientists can be complex and difficult. This gap is not solely the result of perceived difficulty of content, but also a product of alienating aspects of the culture itself. What is our role as science educators in this situation? Should we focus primarily on changing learners so that they conform better to scientific norms, or should we take on some more complex mediating role? What are our responsibilities to learners and to scientific communities? How should we work with our scientist-colleagues who may not share our perceptions? Research alone cannot answer these questions, since they are as much about our