Rigor begins with a commitment to the belief that each individual is capable of learning at high levels (Blackburn, 2012). These high levels of learning reflect the furthest extents of Bloom’s, Webb’s, and Marzano’s educational taxonomies and are affirmed by high expectations that set learners up for success (Bloom, 1975; Webb, 1997; Marzano, 2000). Learners learn best when they are supported and provided with opportunities to demonstrate mastery by showing they can apply what they have learned at these high levels (Williamson & Blackburn, 2010; Wagner, 2008). In effective, rigorous classrooms, learners take the lead on their own cognitive development by actively and passionately engaging in the work of learning (Prince, 2004; Hattie, 2009). This prepares learners to deeply understand complex content and develops the skills and habits needed to think at the higher levels of Bloom’s Taxonomy, including analysis, synthesis, and evaluation (Bloom, 1975; National Research Council, 2001). Ultimately, rigor equips learners to attain mastery of learning that can be transferred and applied across academic and real-world contexts.