Master limited partnerships (MLPs) are limited partnerships that trade on public exchanges in the form of units, similar to common stock. MLPs have several advantages relative to traditional C corporations (C-corps) that have resulted in their frequent use to finance energy-infrastructure assets. The general partners (GPs) retain control of the assets placed in the MLP, can drop down assets to the MLP, often at advantageous prices, and receive incentive distribution rights (IDRs). IDRs increase the GPs' share of the distributions over time, which in turn affects the MLPs' cost of capital. MLPs do not pay taxes at the entity level, which increases the amount of cash that can be paid to GPs and unitholders. MLPs trade on the basis of their yield and the stability and growth of their distributions. This technical note provides a brief history of MLPs, a description of their key features and terms, and several approaches to valuing them.