After more than 15 years since the Agile Manifesto and extensive research on agile software development (ASD) for nearly three decades, a comprehensive body of knowledge is available and is constantly growing. ASD is considered an effective way for managing software development projects in environments characterized by rapidly changing requirements. This study aims to shed light on the existing knowledge on ASD by applying a structured literature review and computer aided analysis consisting of distinct text mining techniques. We analyzed a sample of 1,376 papers and provide results from articles among relevant information systems research as well as computer science conferences and journals. Based on our approach, we are able to (1) evaluate key articles and journals, (2) analyze the development of ASD research in the last three decades and, most importantly, (3) identify research foci of the past as well as gaps in our knowledge on ASD.