Fifty years ago, the National Academy of Engineering (NAE) was founded by the stroke of a pen when the National Academy of Sciences Council approved the NAE's articles of organization. Making a World of Difference commemorates the NAE anniversary with a collection of essays that highlight the prodigious changes in people's lives that have been created by engineering over the past half century and consider how the future will be similarly shaped. Over the past 50 years, engineering has transformed our lives literally every day, and it will continue to do so going forward, utilizing new capabilities, creating new applications, and providing ever-expanding services to people. The essays of Making a World of Difference discuss the seamless integration of engineering into both our society and our daily lives, and present a vision of what engineering may deliver in the next half century.