Taking as its point of departure the research interests of Esa Itkonen, this volume draws together perspectives from linguistics, the philosophy and methodology of linguistics, and the history of linguistics to encourage critical reflection and further understanding of the nature of and connections between these disciplines. The first part of the volume addresses the nature of language from different perspectives, examining some of its fundamental features and its connections to other phenomena. The second part engages in the question of how language should be studied by focusing on different methodological issues across a range of examples. The third part showcases the importance of looking back on the history and development of linguistics, while the typological and empirical studies in the fourth part demonstrate how linguistic methodology works in practice. A separate introductory chapter discusses interconnections between the three fields of research covered by the volume. These sixteen contributions, featuring work from both eminent and emerging researchers, come together to illustrate the diversity and the unity of linguistics and to connect linguistics with its meta-research, making the volume relevant to all researchers within the various subdisciplines of linguistics.