An overview presentation by the XSEDE ECSS Workflow Community Applications Team. The talk introduces scientific workflows through examples in different scientific domains, considering both their common features and their differences. The talk presents a survey of several workflow toolkits, summarizing their capabilities and the types of problems where they have been applied. Two workflow toolkits (Pegasus and Apache Airavata) are presented in greater detail, illustrating their capabilities through their application to earthquake science and astrophysics, respectively. The goal is for attendees to identify and understand different types of scientific workflows, to have an overview of different tools that are available, and to learn how to engage different workflow development communities.