This book introduces interior design as a conceptual way of thinking, which is about ideas and how they are formulated. Now in its second edition, the book is enlarged to include topical subjects such as artificial intelligence, sustainability and climate change. The book prepares designers to focus on each concept independently as much as possible, whilst acknowledging relative connections without unwarranted influences unfairly dictating a conceptual bias, and is about that part of the design process called conceptual analysis. The major themes of this second edition of Interior Design: Conceptual Basis are the seven concepts of planning, circulation, 3D, construction, materials, colour and lighting, which cover the entire spectrum of a designer activity. It is assumed that the site, location, building and orientation as well as the client brief of activities and needs have been digested and analysed to provide the data upon which the design process can begin. Designed as a highly visual illustrative book, as the interior design medium demands, the hands-on creative process of designing is detailed with original drawn illustrations. Concentrating on the conceptual process of designing interiors, and defining what these concepts are, this book helps the designer to organise his/her process of designing and to sharpen the links between the various skill bases necessary to do the job. This book is stimulating for students and instructors alike and is aimed at any student who maybe majoring in interior design, interior architecture, architecture, design thinking or furniture design. It is also useful reference for students of design management and design leadership.