How school librarians focus on activating critical thinking through traditional literacy development can proactively set the stage for the deep thinking that occurs in all literacy development. The critical-thinking skills students build while becoming accomplished readers and writers provide the foundation for learning in a variety of environments. This "Knowledge Quest" issue explores student engagement in understanding and using data and graphics, cultivating global and visual literacies, and applying inquiry processes--all of which require skills in observation, questioning, and making connections--skills that evolve through traditional literacy development. The school librarian's role in ensuring students master skills essential for success in their future academic and real-life experiences begins with supporting their development of critical thinking as learners work toward proficiency in traditional literacy tasks.