Writing and the sciences are intricately linked. Without writing, science would not exist -- and could not be funded, communicated, replicated, enhanced, or applied. Further, writing helps scientists (and students) understand the science, explain the results of research in a greater context, and develop new ideas. Working from this philosophy, this book primarily addresses undergraduate STEM majors and minors who want or need to improve their scientific writing skills. Grounded in the basics of rhetorical research and scientific writing practices and guided by the authors' experiences in the classroom, this book makes the case that writing is an essential component of science regardless of the stage of the scientific process, and that it is in fact a component of thinking about science itself. Featuring student-centered stories that place each topic in context and suggestions for practice, Hanganu-Bresch and Flaherty arm STEM students with the skills to enhance critical thinking and cultivate good writing habits.