A public inquiry with a suitably arranged questionnaire holds a certain place among the methods used in evaluating and selecting the subject-matter to be taught in a certain subject. In order to investigate the basic subject-matter in science we chose a questionnaire with items of the subject-matter, in which the respondents were allowed to add further items in each section and at the end of the questionnaire they could express their views concerning the matter in question. The questionnaire was compiled on the basis of an analysis of technical, agricultural and other specialist literature, and on the basis of analyses of existing syllabi of science subjects and the suggestions of some teachers. At the beginning of 1967 we carried out a preliminary test of the structure of the questionnaire, of the accuracy of the formulations of each of its items, and of the appropriateness of the seven-point scale chosen for marking. After its final arrangement the questionnaire with 328 items was presented to the public between May and July 1967. The questionnaire was to be answered by science teachers and masters, by technicians and engineers from factories, and by scientists and other specialists from universities and scientific institutes. In processing the results it was first found that the questionnaire contained a representative selection of the basic science subject-matter under investigation, and that the respondents kept all the time the same or approximately the same scale of evaluation. It was also found that the members of various groups of respondents always gave relatively the same judgement on a certain subject-matter and the differences in judging individual items did not show any disturbing irregularities besides those that can be explained by accidental fluctuation. In our inquiry, groups of more than 200 respondents give reliable average results. But groups of fewer than 120 members show results of little reliability. Complete results of all the respondents can be characterized as homogenous; differences between average results of different groups of respondents which we chose according to certain criteria, are statistically significant as expected. In groups of respondents classified according to sex, men appraised the subject-matter generally higher than women; in groups classified according to occupation, the subject-matter was evaluated highest by teachers and professors; in groups classified according to the place of work, highest results are given by secondary general school teachers, and in those classified according to age, the subject-matter is assessed highest by the older respondents. In the final classification of the subject-matter into groups according to its significance, we chose, instead of the usual classification, the size of the standard divergence. We classified the subject-matter according to the standard divergence into five groups, equal as to the significance of the subject-matter but each group having a different number of items. The largest group is the middle one, which also corresponds to the needs of practical life. The final distribution of the average results of the classification of the subject-matter into individual groups agrees basically with the theoretical (expected) distribution. The results confirm that, if certain conditions are observed, public inquiry is a significant method of evaluating and selecting the subject-matter of a subject. Thus the results of the inquiry can be made use of, while respecting the results arrived at by other methods (i.e. historical, comparative, analytical, experimental methods, results of seminars, etc.), to find out the most important subject-matter in science teaching, to observe the pedagogical principles of systematizing and planning the subject-matter, to prepare draft curriculums, to prepare textbooks, handbooks, methodological guides and teaching aids.