"Harvard Education Letter" is published bimonthly at the Harvard Graduate School of Education. This issue of "Harvard Education Letter" contains the following articles: (1) Learning Progressions in Science: A New Approach Emphasizes Sustained Instruction in Big Ideas (Patti Hartigan); (2) Putting the "Boy Crisis" in Context: Finding Solutions to Boys' Reading Problems May Require Looking Beyond Gender (Michael Sadowski); and (3) Building on What We Know: A Retiring School Administrator Reflects on the Conversations We "Ought" to be Having (Laura Cooper). Online version may contain additional articles.