General purpose computer algebra system by Bernard Parisse released under GPLv3. French documentation by Renee De Graeve is for non-commercial use only. The package consists of: - a C++ library (libgiac). It is build on C and C++ libraries: PARI, NTL (arithmetic), CoCoA (Groebner basis), GSL (numerics), GMP (big integers), MPFR (bigfloats) and provides algorithms for basic polynomial operations (product, GCD) and symbolic computations (simplifications, limits/series, symbolic integration, summation, ...). The library can be configured to accept Maple or TI syntax to ease the transition for users of these systems. - a command line interpreter (icas or giac). It can be called from texmacs. - a FLTK-based GUI (xcas). It is a GUI for symbolic computation with several modules added: 2-d and 3-d graphics, dynamic 2-d and 3-d geometry (exact or numeric), spreadsheet, programming environment. Bernard Parisse is the main author of the CAS of HP40G and HP49G calculators. This port is statically linked against snapshots of FLTK-1.3.x (http://www.fltk.org) and of CoCoALib (http://cocoa.dima.unige.it/cocoalib) WWW: http://www-fourier.ujf-grenoble.fr/~parisse/giac.html