It has become exceedingly important to understand the precise molecular profiles of the nearly 40 trillion cells in an adult human because of their role in determining health, disease, and therapeutic outcome. The National Institutes of Health (NIH) Common Fund-supported Single Cell Analysis Program (SCAP) was designed to address this challenge. In this review, we outline the original program goals and provide a perspective on the impact of the program as a catalyst for exploration of heterogeneity of human tissues at the cellular level. We believe that the technological advances in single-cell RNA sequencing and multiplexed imaging combined with computational methods made by this program will undoubtedly have an impact on broad and robust applications of single-cell analyses in both health and disease research.