Anna Barbara and Anthony Perliss have written a very thought-provoking book. When we mentioned it to an Italian architect friend, she was quite amazed at the idea of how this could be done and to some extent the complex problem posed by the title has not been fully answered. The book also raises the question, what is architecture? Most of us have a preconceived notion that it is buildings and the built environment, but if we experience places through the sense of smell, as this book sets out to do, then it is rarely the actual buildings that produce the odour but the activities associated with them. Smells that we encounter are, mainly, produced by the function of the buildings or spaces and by the circumstances relating to them. Examples given of structures that do have a definite identifiable smell to them are often vernacular buildings and the materials that they are made of, such as animal skins, dung or clay have their own particular scent which is not present in the cities of today.