This document provides briefing notes on decentralization from the World Bank. It is divided into four chapters that cover: 1) definitions and rationales for decentralization, 2) issues in designing political, fiscal, and administrative decentralization systems, 3) impacts of decentralization on specific sectors and services, and 4) potential cross-cutting impacts of decentralization related to equity, macroeconomics, growth, and accountability. The notes are intended to highlight the broad range of issues that must be considered regarding decentralization and summarize key topics for practitioners.