This book offers a complete overview of the complex topic of reasonableness. Ranging through ethics, political theory and legal theory, the author shows how âreasonableâ is an unescapable evaluative term. One uses this concept to evaluate positively or negatively â âit is unreasonable!â â both our conduct and that of others. However, we are often not aware of the presuppositions behind our use of the concept. Especially the legal use, both in civil and in common law, reveals a large variety of meanings and the so called âmultifacetednessâ of reasonableness. In an age in which the environmental crisis or âglobal climate changeâ threatens our style of life we badly need criteria of evaluation that we all can share. This book therefore provides a unitary conception that connects to the ethics of virtues as the fabric that links the many uses of âthe reasonableâ.