"Transformational Professional Learning" is a periodically published e-newsletter designed to influence what educational leaders think, say, and do to improve teaching and learning by promoting deep understanding of important issues, the transformation of beliefs and assumptions, and a stream of powerful goal-focused actions. There are two articles in this issue. In "Two Tiers Too Many: Performance Training Sects and Professional Development Apartheid," Dennis Sparks writes that the most powerful forms of professional learning are aligned with the type of teaching that a school or system values, which in turn is based on the learning outcomes of all students. He asserts that the type of professional learning that equips all teachers to prepare all students for a life of contribution in a knowledge economy and a knowledge society cultivates teachers' deep understanding and professional judgement and provides them with a varied and flexible repertoire of instructional approaches. In the second article, "What Do You Think? Develop Clarity Regarding Assumptions and Deep Understanding of Important Subjects," Sparks writes that assisting educators in developing clarity regarding their assumptions and acquiring a deeper understanding of subjects related to leadership, teaching, and human learning are fundamental and often overlooked aspects of professional development. In both articles Sparks recommends ways to examine one's own assumptions about the issue; deepen one's understanding of the issue; and engage in next action thinking relating to the issue.