T he Architect’s Handbook of Professional Practice, published by the AIA since 1920, has become the definitive information source of architectural practice for over 90 years. While major changes have altered the demand for design and architectural services in the intervening decades, this handbook has kept pace and has risen in value to the profession. The 15th edition, which you are about to read, reflects a range of current AIA initiatives aimed at improving the built environment and public well-being. At the same time, it reflects a contemporary ethos with emphasis on diversity and inclusion, small-firm culture, sustainability, and evolving representational and project delivery methods such as BIM and architect-led design-build. How does the Handbook reflect these factors? By including expanded content for emerging professionals, such as information on career development, as well as expanded content for established architects who work for or own small and midsize fi rms. Case studies and targeted articles, written by real-world practitioners, portray a discipline that has been recently segmented by economic circumstances, technological change, and generational difference. Licensed architects, who are united in their professionalism, and those on the path to licensure—both are represented here, united in their desire to meet a high standard of excellence. Architecture has become an adaptable enterprise for a world that requires nimbleness, pragmatism, and no small amount of ingenuity. From one architect to another, I think you will appreciate the strength of the knowledge base on which this 15th edition rests. I think you will also fi nd it to be an indispensable tool in a time of great change and even greater opportunity for architects.