This document describes the Extended Source Analysis Software (XMM-ESAS) package for the analysis of EPIC MOS and PN observations. This ESAS package, which relies on XMM's Science Analysis Software (SAS) and HEASARC's FTOOLS, includes routines which create source and model particle background spectra and exposure-corrected, background-subtracted (particle and soft proton) images. The spectra and images are produced for user-defined regions within an observation field of view. The output files are in standard FITS format. Software for mosaicking multiple observations of not necessarily co-aligned observations is included in this package. Note: This documentation is meant to complement the document COOKBOOK FOR ANALYSIS PROCEDURES FOR XMM-NEWTON EPIC OBSERVATIONS OF EXTENDED OBJECTS AND THE DIFFUSE BACKGROUND.