Gregory Johnson (left) “stumbled” into accounting as an undergrad at Adelphi University in New York. A summer internship at PricewaterhouseCoopers led to a full-time job after college. His passion for the field drew him to the AICPA, where he worked for 16 years overseeing diversity programs. Yesterday, he took over as executive director of the National Association of Black Accountants. The Washington Post Q&A starts at “Tackling Accounting’s Long Racial Division,” here…