The title of this edited book, »To Understand Is to Be Free«, is a condensation of the thoughts of 17th-century Dutch philosopher Baruch Spinoza from his work »Ethics« (1677). He gave Part V of the work the title “Of the Power of the Understanding, or of Human Freedom”. This body of thought has given rise to the well-known quote “To understand is to be free”, which has become a widely used popular saying. The fundamental message of the philosopher for humanity is the value of freedom, and of understanding as a tool that leads to it. On the book’s cover is a statue of renowned Slovak scholar and polymath Matej Bel (1684–1749), who also advocated the prioritization of understanding in teaching and communication. This year we commemorate the 340th anniversary of his birth. We hereby present to our esteemed readers an international edited book that approaches the dual theme of comprehensibility/understanding and freedom from multiple perspectives. Authors from 10 countries have come together to explore these themes from the standpoints of such varied fields as linguistics, translation studies, literature studies, language didactics, medicine, and legal communication.  The idea of accessibility informs this book in several ways: in the subject matter of the various chapters, but also in the way they are presented, making their respective fields accessible to those from other (closely or distantly) related fields. It is in this spirit that each chapter is followed by a plain-English summary. It is also for accessibility’s sake that we have chosen to publish this book in English only: to make all the chapters accessible to a worldwide audience.