In this research study, we performed a "content analysis" of selected introductory programming textbooks for three languages to examine which software development concepts are emphasized in these books. Our goal was to determine which concepts are considered to be most representative of software development based on the topics emphasized by the textbook authors. We counted how often programming words appeared in samples of C++, Java, and Python books. We discovered which concepts are consistently supported for all three languages. We also noted those concepts that are favored by just one or two languages. Our summarized results lead to several conclusions that are relevant to the choice of a language for an introductory programming course.