"My first opinion of Paul was soon confirmed. He turned out to be an admirable tutor. In two years I'd learned all he had to teach, but we went on together... probing into the unknown, investigating, recording, searching... always searching... until gradually the sweep of our research began to assume a single direction... and to this aim we finally turned all our energies. It took us years of unrelenting work to discover what we were seeking. Then, one night... out of sight and sound of the rest of the house... our efforts were rewarded."