Zusammenfassung: This set of computer programs for stock assessment uses MS FORTRAN 77 version 4.1* for all the programs. The programs will compile under version 3.2 of MS FORTRAN 77, however the Open statements with file types “Unknown” must be changed to “New” or “Old” depending on the expected status of the file. The “shell” called TUNE is used to build the appropriate batch file for submission of the multiple runs used for calibration. Each of these programs is an interactive stand alone module, each can be used independently of the others. This report gives an outline of how and where these programs fit into an analytical process. A set of disks with the source code and the executable (*.EXE) files is available from the editor or the programs can be copied from the ICCAT Secretariat in Madrid; an Annex to this report containing a listing of the source code is also available. A glossary of terms commonly used in the assessment process is presented in Appendix I.