Information presented in this document and related to scientific data is based on in-flight observations, except for Section 3.3.9 which discusses some effects of pile-up on spectral fits that are based on model simulations using the XMM-Newton Science Simulator (SciSim). The SciSim tool was developed before launch by the SOC for modelling XMM-Newton observations. The last version of SciSim (V4.0) was released in Jan 2005 and kept operational until July 2010, when maintenance and public distribution of SciSim was finally stopped.