This document provides an introduction to the Core Infrastructure Initiative (CII) Best Practices Badge. It discusses the motivation for developing the badge, which was to encourage open source projects to follow best practices that increase security and quality. The badge criteria focus on areas like change management, reporting, quality, security, and analysis. Projects can self-certify that they meet the criteria to receive a badge at no cost. Over 3,200 projects are now participating in the program. The badge levels of passing, silver, and gold require meeting additional criteria. The CII aims to identify best practices and encourage their adoption to improve trust in critical open source infrastructure.