Course authoring tools are products designed for creating online courses. Most will be intended for use by people with limited or no technical skills, although some may also support customisation by software developers.
They are primarily used by content owners, subject matter experts and instructional designers to support in-house or out-sourced course development projects. They can be especially useful for rapid or agile development, and where you want to customise content for your audiences.
Some are products that you download, others are network installed or operate on a Software-as-a-Service (SaaS) model. Most will support team collaboration to some extent.
An important consideration is the support for different publishing models, with options ranging from stand-alone courses to standards-based integration with a Learning Management System.