In 2006, after receiving the Division 15 Career Award, Alexander delivered a keynote address entitled "Evolution of a Learning Theory: A Case Study." This presentation was a clarion call for greater respect for and attention to scientific speculation in educational psychology as a critical component in theory building. To build her case, Alexander drew on the writings of a provocative cosmologist, Joao Magueijo (2003), as an analogy to the processes and experiences that led to the Model of Domain Learning (1997, 2003)--her theory of academic development. Within the published text of her presentation, Alexander outlined the confluence of factors that instigate or inhibit scientific speculation and the conditions that transform such speculation into empirically supported theories. For this topical collection, the premises, factors, and conditions touched on in that keynote delivered 16 years ago will be revisited and re-examined in light of contemporary practices and prevailing orientations in educational psychology.