In an attempt to broaden the understanding of the physical environment's role on the visitor in the exhibition. This book investigates the impact of colour on the visitor's attention within the interior space of the auto-showrooms. It focused on three variables which presented by colour as an independent variable, highlighting exhibits as a mediator, and the visitor’s attention was the dependent variable; Where developed a numeric scale to measure the impact of colour on the visitor’s attention, and practical experiment to answer the research question by both quantitative and qualitative approaches. The results showed that there is a significant relationship between the colour and the visitor’s attention by highlighting the cars and brands within the interior space of the showroom. The authors have observed that there is indifference in applying the interior design principles and elements in most of auto-showrooms; forgetting the basic goal of the establishing those showrooms is to attract the visitor’s attention into the exhibits; not into the interior constructions. The book is a contribution to fill a gap in knowledge, and it may open new horizons for future studies.