Third party logistics (3PL) involves outsourcing logistics functions like warehousing and delivery to a third party provider. There are four main types of 3PL providers: standard 3PLs that perform basic functions; service developer 3PLs that offer value-added services; customer adapter 3PLs that take over a customer's logistics; and customer developer 3PLs that fully integrate with a customer. Using a 3PL provides advantages like cost savings, low capital needs, and flexibility, but can result in lost control and challenges with reverse logistics. The 3PL industry is growing rapidly, doubling in revenue compared to GDP, as most large companies now use 3PLs to improve supply chain operations.