Welcome to Qu-Prolog 11.9. Qu-Prolog 11.9 is an extended Prolog with built-in support for quantifiers, object-variables and substitutions. It is designed as an implementation language for systems such as interactive theorem provers. This version of Qu-Prolog also has support for multi-threading and high-level symbolic communication using Pedro. The doc/user directory contains a user manual and the doc/manual directory contains a reference manual both as a .pdf document and as a HTML document. For the HTML document point your web browser at doc/manual/MAIN.html The examples directory contains some example programs that use the extensions of Qu-Prolog. These examples are referred to from the user manual. If you have any comments or problems please email to pjr@itee.uq.edu.au