This document provides an overview of log management and security information and event management (SIEM). It explains that SIEM systems evolved from separate technologies like log management systems, security log/event management, security information management, and security event correlation. A SIEM system provides centralized log collection, normalization, storage, and analysis. It allows security events from different systems to be correlated to detect patterns and automated threats. The document emphasizes that SIEM provides context around security events to help analysts investigate incidents.