Practical Advice to Teachers: Fourteen lectures given at the foundation of the Waldorf School, Stuttgart, from August 21 to September 5, 1919 by Rudolf Steiner (CW 294)
For your convenience, below is a zip file of this entire set of lectures. It does require that you have an unzipping utility of some kind on your computer. For you mac people this is built in.
The Entire Book Practical Advice to Teachers