This document provides an overview of computerized physician order entry (CPOE) systems. It defines CPOE and describes its key features and functions, including ordering, decision support, safety checks, and improved documentation. The document discusses common CPOE hardware and software and examines legal/ethical issues. It outlines both the advantages of CPOE in reducing errors and costs and the disadvantages such as high implementation costs. The document also reviews studies on CPOE's impact on patient safety and productivity issues during implementation.