The Solfeggio tuning forks have frequencies that are encoded in the biblical book "Numbers". For a long time they were used only for a very small group of insiders. They form the basic frequencies of the universe. They can be used to construct (DNA) or destroy (Walls of Jericho). In the old system of gematria each Hebrew letter has a specific number. Pythagoras had a similar system, because he thought that everything can be expressed in numbers which together add up to a digit from 1 to 9. With those 9 tuning forks we have the most powerful and therapeutic tool for personal transformation. We give courses for their application.