Trademark licensing allows a registered trademark owner to grant permission to another party to use the trademark. It provides benefits to both parties, allowing the owner to expand their business and the licensee to generate revenue with less investment. However, there is a risk that the licensee could exploit the trademark more successfully than the owner or that unauthorized usage could occur. Key principles for trademark licensing include source identification, where the trademark must be connected to the owner, quality control to preserve the brand's reputation, and connection in the course of trade to ensure quality control is maintained.