This document provides an overview of Application Link Enabling (ALE) in SAP systems. ALE allows for distributed yet integrated business processes across separate SAP systems. It uses message-based integration where IDocs are generated and exchanged between systems. The document outlines the ALE architecture, objectives, processes for outbound and inbound integration, configuration settings, and techniques for exchanging different types of data like transactions, master data, and control data between systems. It also previews a hands-on agenda for demonstrating ALE functionality.