This article is part of a special issue of the Journal of Technology and Teacher Education (JTATE). It introduces and summarizes how the six articles describe specific ITEST teacher development projects, provide portraits of these projects, and address important themes that cross ITEST professional development and STEM professional development more generally: building links between informal and formal education; using technology in innovative ways; integrating STEM content into professional development; reaching and engaging underrepresented populations; developing innovative professional development; and tightening the research/practice cycle.