What is jewellery? This new publication is a reflection on that question. Here is an interdisciplinary approach transcending the familiar categories crafts or art, applied or fine. What matters here is exploring what jewellery is not what it looks like. Thinking Jewellery is the distilled result of a colloquium with the same title that has been jointly hosted since 2005 by the Idar-Oberstein course in gem and jewellery design by Trier Polytechnic and the city of Idar-Oberstein. Each year in May more than a hundred jewellery designers, students and academics from all over Europe convene in Idar-Oberstein to conduct a comprehensive discourse without boundaries on the theoretical foundations of jewellery.The publication contains the most interesting lectures given over the five years since the Colloquium was instituted by major artists in jewellery, distinguished ethnologists, philosophers, psychologists, cultural anthropologists and scientists. Lavishly illustrated to showcase the objects discussed, it documents the standards so spectacularly achieved by the Idar-Oberstein Jewellery Institute. The book Thinking Jewellery fascinatingly exemplifies the productive interaction of theoretical reflection and practical execution.This book marks a departure towards a theory of jewellery, something hitherto non-existent. The question is: what do I see and what's behind it?