The teachers are the professionals—responsibilities include more than the education of students. The chapters in this book are meant to sharpen teachers’ observational skills so they can recognize the issues and circumstances that require attention to and planning for conducting science inquiry safely. No single book or series of books can anticipate all the safety issues that can arise in an active science program. This chapter focuses on how the habit of observing and thinking about science lessons with common sense and safety in mind will keep teachers, as well as students, safe. And remember, you, the teacher, remain responsible for everyone and for everything in your classroom—an awesome responsibility—and a world of opportunity.