This guide sets out the law and practice of intellectual property licensing across patents, copyrights, trademarks, and trade secrets. It begins with what a license is and what distinguishes exclusive, sole, and non-exclusive grants, including the standing consequences that determine who may sue infringers. It then works through scope — rights granted, field of use, territory, term, sublicensing, and assignment — and through the economics of royalties, net sales definitions, stacking, reporting, and audit rights. Separate parts address exhaustion and post-sale restrictions, a licensee's ability to challenge validity, the trademark quality control obligation and abandonment, copyright termination rights, and the treatment of licenses in insolvency. The federally funded technology regime, improvements and grant-backs, enforcement allocation, termination and wind-down, recordation, and diligence complete the treatment.