Summary: Business Expertise is a series of articles on Commoncog that explores the unique approach of studying business. The series is based on the research of Lia DiBello, a Naturalistic Decision Making (NDM) researcher who focused on extracting tacit mental models of expertise in the business domain. DiBello discovered that every successful businessperson shares a common, generalizable mental model of business, which consists of three components: effective operations, market influences, and factors related to business finance and economic climates. These three components are interconnected, and experts in business understand how changes in one component affect the others. Additionally, cognitive agility, the ability to update mental models based on new evidence, is an important attribute of business expertise. The series on Commoncog covers these concepts in detail and provides a framework for understanding business expertise.