Five high school biology textbooks were examined to determine the inclusion of four aspects of the nature of science: (a) science as a body of knowledge, (b) science as a way of investigating, (c) science as a way of thinking, and (d) science and its interactions with technology and society. The textbooks analyzed were "BSCS Biology--A Human Approach" (Kendall/Hunt), "BSCS Biology--An Ecological Approach" (Kendall/Hunt), "Biology --The Dynamics of Life" (Glencoe), "Modern Biology" (Holt), and "Prentice Hall Biology" (Prentice Hall). The same six chapters or sections were analyzed in each textbook, which were the methods of science, cells, heredity, DNA, evolution, and ecology. A scoring procedure was used that resulted, for the most part, in good intercoder agreement with Cohen's "kappa" values ranging from 0.36-1.00. The five recently published biology textbooks in the United States have a better balance of presenting biology with respect to the four themes of science literacy used in this research than those analyzed 15 years ago, especially with regard to devoting more text to engaging students in finding out answers, gathering information, and learning how scientists go about their work. Therefore, these biology textbooks are incorporating national science education reform guides that recommend a more authentic view of the scientific enterprise than similar textbooks used 15 years ago. (Contains 1 figure and 8 tables.)