SAP is the leading ERP software package. The ERP market saw many software packages in its nascent stage but hardly a handful could prove the test of the time and SAP has emerged as the leader. SAP helps to bring the entire business online and integrate the business processes. It provides end-to-end business solutions which means it covers all the processes involved in that arm of the business (e.g Order to Cash, Purchase to Pay, Manufacture to delivery, etc). It has different modules to implement the business processes - Financial Accounting & Controlling (FI/CO), Materials Management (MM), Sales & Distribution (SD) - to name a few.

SAP is such huge software, if you want to explore what's there in it to make a view of it, probably you need to go through a book on the subject which provides the main and important information ... even for people who are working as SAP users in their jobs. As a non-technical user-guide, you can refer the book SAP R/3 for Everyone: Step-by-Step Instructions, Practical Advice, and Other Tips and Tricks for Working with SAP from Jim Mozzullo and Peter Wheatley. This is not a technical book and gives a great overview of the main concepts of SAP software for beginners and SAP users. A practical and jargon-free book which provides you with a basic understanding of the SAP software and allows you to carry out common business transactions as a SAP user.