Good price / quality ratio 172

I am more than amazed that a book with such a low price is as good!
In the first part we find a kind of small summary of the pendulum, dowsing (what it is, its history, types of clocks, how to address it, etc ...) and in a second part very affordable practical exercises to achieve. So please have your clock, and no need to buy books overpriced when it is waiting for you!