What is new in CIA V4.0? New and improved algorithms o New transient correction: fs using an improved implementation of the Fouks-Schubert transient correction leads to better results and to a reduction in processing time up to a factor of 20. o Improved dark correction vilspa using a second order time-dependent correction reduces the dark uncertainty by up to 30 %. o Access to long-term transient and variable flat-field algorithms routines via the SLICE package. o back_project allows the possibility to back project a raster MOSAIC to a set of EXPOSUREs to verify stability and deglitching. o raster_scan has now the option /weight to use the weighted mean to create a mosaic. New and improved functionality o CIA is now Y2K compliant. o Handling of Solar Sytem Object observations. o Handling of polarisation observations. o The new tool ximage provides improved functionality for astronomical image display, expecially for the analysis of data from raster observations. o The new tool xcvf provides an interface to the spectral analysis package ISAP. o Inclusion of algorithms to treat faint sources for circular variable filter (CVF) observations. o No-blocking widgets were introduced so command-line and widgets can be used in parallel. o Help functionality was improved. o The automatic slicer spdtoscd now warns about saturated pixels. The new option method='nomode' slices only according to h/w changes of ISOCAM and ignores s/w settings like the obs-mode. o High level colour correction routine corr_colour is available now. o The naming convention for theoretical PSFs was rationalized. o isocont handles now IRAF FITS files and has the additional options cut1, cut2 and thick. o CIA's start-up files were rationalized. o Obsolete algorithms for transient correction and deglitching were removed.