The basic tenet of inquiry learning is that students arrive at an understanding of the subject matter by engaging in self-directed investigations. The foundations of this mode of learning are derived from three related fields of study. Psychological research on scientific reasoning revolves around the cognitive processes involved in inducing knowledge from empirical data, and intends to give an account of the problems students encounter in performing these processes. These learning difficulties (should) serve as a starting point for educational research into the effectiveness of support or scaffolding that can be used to overcome known skill deficiencies. Research and development of software tools and environments addresses the ways in which this support can best be offered to the learner so as to enhance learning processes and outcomes. This chapter outlines recent trends and issues in these three research areas, and attempts to synthesize key findings in order to identify the latest advancements in inquiry-based learning.