Concepts from architects' minds evolve through sketches and as a mode of transference are conveyed to the finished building. This book compares qualities of sketches to reveal unique approaches to the instruments of thinking in which all architects engage. It provides new insight into the relationship between architectural sketches and the process of creative manipulation. Sketches comprise a thinking mechanism, and through the qualities of ambiguity, quickness and change, they initiate a dialogue for architects. As a medium to facilitate communication, recording, discovery and evaluation, their pertinence lies in their ability to exhibit both the precise and the imprecise. Exploring four related theoretical approaches, play, memory-imagination-fantasy, caricature and the grotesque, the book shows how imprecision stimulates imagination to conceive new forms in the dialogue of architectural sketches.