The authors describe the difficulties with attempting to understand and study historical thinking of young learners and understanding teachers and their epistemological practices. The authors begin with an example of how a technical glitch in research and practice can create theoretical troubles. They continue the chapter with more examples of difficulties that are met when conducting historical thinking research with young audiences and then present some tentative ideas of how they may be resolved. They describe how young children will usually not tell the interviewer everything they know when being interviewed. They suggest that students may focus on a specific part of the question or not be able to properly articulate all they know on a historical subject. The researcher should rephrase the question and be patient with the students as they struggle to articulate their points. Socio-cultural differences between the children and the researcher can also cause issues and often students will tell the researcher what they think they want to hear. It is important for researchers in history education to have a starting point from which to measure any changes, which is difficult when students, especially those in the United States are offered very little opportunity to develop historical thinking and reasoning skills. The authors continue with a study of teachers’ epistemology of historical thinking and understanding, which leads to a deeper and richer understanding of the past. However, what counts as understanding and what counts as knowledge in historical thinking is very important and varies for different groups. The authors discuss their focus on history education research on beginning teachers and their pedagogical decision-making and domain knowledge and how it relates to their use (or misuse) of historical thinking. It is important to make the distinction between history and the past and historical recall and thinking. The authors also discuss what is significant when discussing and studying historical thinking. They conclude with a discussion of “ambitious history teaching.”