Bonnen and colleagues introduce application program interfaces (API) as a building block for the digital economy, as well as a product that facilitates building those blocks in an ever-changing digital world: SAP API Management. They cover getting started; designing, developing, and managing enterprise APIs; consuming APIs and API analytics; and next steps. Their topics include managing the end-to-end lifecycle of API's, managing enterprise API's, monetizing APIs with API products, API program, and recent and future developments. Annotation �2020 Ringgold, Inc., Portland, OR (protoview.com)