From readability to operability, this book presents a number of experiments to analyze the characteristics of paper and digital displays in reading and writing. Why is it easy to read on paper? Why is it easy to concentrate on reading on paper? Why is it easy to think while writing or drawing on paper? This book answers these questions based on cognitive experiments on media. Paper is easy to read because it is easy to handle. If we emphasize the strengths of paper, paper is an operation media rather than a presentation media. These experiments also indicate how to develop digital media for reading and writing. This book will interest those who want to gain a scientific understanding of reading and writing on paper, those who want to work more effectively by selectively using paper and digital tools (e.g. knowledge workers and educators), and those who develop digital devices or services for reading and writing.