QBF Solver Evaluation Portal. QBF Evaluations are a series of yearly events with the purpose of assessing the state of the art in the field of QBF solvers and QBF-based applications. Up to the third event in the series, the evaluation was run on a non-competitive basis, i.e., there were no winners and losers. Starting from 2006, QBFEVAL becomes a competitive event. We warmly encourage developers of QBF solvers to submit their work, even at early stages of development, as long as it fulfills some very simple requirements. We also welcome the submission of QBF formulas to be used as test instances for the evaluation. People thinking about QBF-based techniques in their area (e.g., formal verification, planning, knowledge reasoning) are invited to contribute to the evaluation by submitting QBF instances of their research problems.