We are attempting to move to using FITS format files for all XSPEC input and output files. In particular, XSPEC now fully supports FITS format spectral and response files. The FTOOLS package (also available by anonymous ftp from legacy.gsfc.nasa.gov) contains a large number of tools for manipulating FITS format files, including a number of specialised tools for spectral and response files. Some of these tools are listed in Chapter 7.