DIFMAP: Difmap is a fast, flexible, editing and mapping program. While it is primarily intended for single polarization continuum VLBI data, it has been used to map VLA and other connected-element interferometer dat. It is designed to work on one source at a time and takes advantage of this and the large internal memory available in the current generation of workstation to minimize the time spent reloading data and regenerating models. Difmap also provides the user with a wide range of interactive plots available with a single command. This frees the user from time-consuming specification of input parameters, and encourages a better familiarity with the data. (from the Introduction to 'The Difmap Cookbook' by Greg Taylor) The current version is 2.3a This is the second major version of Difmap. Instead of reading the Caltech VLBI merge format, this version reads UV FITS files directly. Support for UV FITS files is limited to single-source files containing one frequency-id (one set of possibly differing IF frequencies). Multiple sub-arrays, IFs, spectral-line channels and polarization are now supported. DifMap is available at I.R.A. on DEC-alpha and Linux work-stations. To start the program enter: difmap At the difmap prompt type: 0> help difmap Difmap will list a set of general help topics, followed by a list of all difmap command. Type help and the name of any of these commands to get further help. (Hint: type help observe to get started). To get out difmap, type: 0> exit The DIFMAP User's Guide are available in two diffent forms: Postscript files at the address: http://www.ira.inaf.it/ira-docs/calcolo.html Manuals at the room 307 Contact persons: F.Mantovani fmantovani@ira.inaf.it T.Venturi tventuri@ira.inaf.it F.Tinarelli tinarelli@ira.inaf.it