The present volume collects some of the talks given at the Bertrand Russell Colloquium on Exact Philosophy, attached to the McGill University Foundations and Philosophy of Science Unit. It also includes a paper, on Bertrand Russell's method of philosophizing, read at the memorial symposium held at Sir Gorge Williams University shortly after the philosopher's death. All the papers appear here for the first time. Unlike many a philosophy of science anthology, this one is not center­ ed on the philosophy of physics. In fact the papers deal with conceptual and, in particular, philosophical problems that pop up in almost every one of the provinces of the vast territory constituted by the foundations, meth­ odology and philosophy of science. A couple of border territories which