During the past decades, innovation research has yielded countless empirical studies in a variety of disciplines. For all this quantity, we still lack an adequate understanding of basic qualities and mechanisms of its central subject. Which processes and conditions bring innovation about? How does it spread? And what is its genuine nature? Critics argue that these shortcomings have their roots in the conceptual limitations of established perspectives on innovation and in the fact that researchers confine themselves to studying technical and scientific novelties or marketable products. This self-restriction stands in marked contrast to the observation that innovation plays an important role in contemporary societies. The term is at least ubiquitous and its usage common in all societal fields. In this introduction to this HSR Special Issue, we subscribe to this critique and argue that the conceptual reductionism comes along with severe methodical and methodological limitations. These become manifest in a joint dominance of quantitative indicator-based research and ethnographic single case studies. Thus, researchers of innovation disregard a variety of possible data types and forms of analysis and rarely apply complex designs. It is also not common to consider the combination of multiple types of data and analysis in mixed methods approaches. The most serious issue, however, is that mainstream innovation research remains ignorant of a multitude of potential research questions and thereby loses sight of whole areas of interest. An overview of the empirical studies in this HSR Special Issue shows that the range of methods used is wider at the edges of the field of research. In order to relate these methods to each other and to the theoretical foundations of innovation research, we suggest a middle-range debate on methodology.