The Spiritual Guidance of the Individual and Humanity: Some Results of the Spiritual-Scientific Research into Human History and Development by Rudolf Steiner (CW 15). These are placed in the written works section of this site because they have been revised by Dr. Steiner for publication.
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 The Spiritual Guidance of the Individual and Humanity