Considering the longevity of objectives related to students’ conceptions of the nature of science, it is more than intriguing that the first formal instrument to assess students’ conceptions was developed about 50 years ago (Wilson, 1954). The development of instruments to assess NOS has a long history and is extensive enough to constitute separate treatment in this review. Although it can be argued that placing the discussion of assessment first would provide an important context for the review of the research, it can be equally argued that a discussion of the varied assessments would be too abstract without the context of the specific research investigations. Consequently, the review of NOS assessment has been placed at the end of the review. However, this should not impede those who wish to read the section on assessment first. In Wilson’s (1954) investigation, which was primarily an attempt to validate an instrument known as the Science Attitude Questionnaire, a sample of 43 Georgia high school students was found to believe that scientific knowledge is absolute and that scientists’ primary objective is to uncover natural laws and truths. The most extensive early attempt to assess students’ conceptions of the nature of science (Mead & Metraux, 1957) involved a nationwide sample of 35,000 student essays on the topic “What Do You Think About Science and Scientists?” Mead and Metraux drew a randomized sample that was representative with respect to age, gender, geographic distribution, and socioeconomic status. Their qualitative analysis of the data yielded findings that were consistent with Wilson’s (1954) findings on both attitude toward science and students’ understandings of the nature of science. It is interesting to note that the earliest studies related to the nature of science often included assessments of attitudes or conflated the nature of science with attitude toward science.