This book arises from the identification of the role of SME support institutions in Central America and the writing of more than 100 case studies on the trajectory of small and medium enterprises in the region. The comparison between the needs of these enterprises and the services offered by the institutions led us to the conclusion of the importance of creating a more effective link between them, which we call the "Business Extensionist". The process of preparing Extensionists, the results of the first tests of the process and a glimpse of the future are the essence of the document that reaches the reader's hands.