Technological pedagogical and content knowledge (TPACK) presents a dynamic framework for describing teachers' knowledge required for designing, implementing, and evaluating curriculum and instruction with technology. TPACK strategic thinking includes knowing when, where, and how to use domain-specific knowledge and strategies for guiding students' learning with appropriate information and communication technologies. Multiple visual and verbal descriptions reflect evolving recognitions of teacher educators and educational researchers as they have struggled to respond to the challenges in describing and developing teachers' TPACK. This extensive reflection maps the historical acceptance of pedagogical content knowledge (PCK) with the emerging views of and challenges with TPACK. A review of empirical progress in the investigation of TPACK serves to illuminate potential insights, values, and challenges for directing future educational implementations designed to identify a teacher's learning trajectory in the development of a more robust and mature TPACK for supporting them in teaching with current and emerging technologies. (Contains 5 figures.)