This document provides an introduction to third party logistics (3PL). It defines 3PL as a firm that provides outsourced logistics services for a company's supply chain functions. The advantages of 3PL include cost and time savings through expertise, low capital commitment as companies don't own logistics assets, and increased focus and flexibility. Potential disadvantages include loss of control over logistics when using an external provider. The document also outlines different types of 3PL providers and layers of logistics services.