This document provides an introduction to understanding and managing crises in tourism small and medium-sized enterprises (SMEs). It begins by defining what constitutes a business crisis and distinguishing it from insolvency and turnaround situations. The tourism industry is noted as being particularly vulnerable to crises due to characteristics of its products and services. Various models of the typical phases of a crisis are presented, from latent issues to acute problems. Specific reasons for the high failure rate of SMEs and young companies are also explored. The importance of early crisis detection is emphasized through mechanisms like anticipating potential issues and recognizing early warning signs. Endogenous and exogenous causes of crises in the tourism sector are introduced as topics for further examination.