Forest managers willing to take biodiversity into account in their daily work need simple tools to identify the stand features that should be promoted or conserved. The Index of Biodiversity Potential (IBP) is an indirect biodiversity evaluation tool created in France in 2008, based on the rapid field assessment of ten factors. Since its creation, it has benefited from a research and development program that runs to this day. However, the knowledge underlying this biodiversity evaluation tool is currently scattered across many papers, some of which are only available in French, including a seminal one. Until now, no summary document had concisely compiled the scientific background of the IBP. This paper aims to present a comprehensive overview, providing potential users with all relevant information concerning its scope, significance, available tools, and communication materials. The factors that make up the IBP and the scores obtained for a wide range of contexts were calibrated with large-scale taxonomic data. Observer effect was assessed and contributed to refining factor definitions and thresholds, and to shaping optimized training sessions. The IBP has been tested and applied in a wide range of climate and forest types, with numerous training sessions and communication via a large array of media. A sociological study showed that it is now used by a wider range of actors than those initially targeted, thus facilitating discussions and negotiations among experts with different interests. The IBP has spread to 18 countries under the guidance of an international expert committee.