A Way of Self-Knowledge and The Threshold of the Spiritual World by Rudolf Steiner (CW 16/17)
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 Books A Way of Self-Knowledge and The Threshold of the Spiritual World
PART 1: A WAY OF SELF-KNOWLEDGE
1. Introductory Remarks and Meditation 1: The Physical Body
2. Meditation 2: The Elemental (or Etheric) Body
3. Meditation 3: Clairvoyant Cognition of the Elemental World
4. Meditation 4: The 'Guardian of the Threshold'
5. Meditation 5: The Astral Body
6. Meditation 6: The "I" - Body or Thought-Body
7. Meditation 7: The Nature of Experience in Suprasensory Worlds
8. Meditation 8: Beholding Your Previous Earthly Lives
9. Afterword to the 1918 Edition
PART II: THE THRESHOLD OF THE SPIRITUAL WORLD
11. Aphorism 2: Cognizing the Spiritual World
12. Aphorism 3: The Human Etheric Body and the Elemental World (with Summary)
14. Aphorism 5: The Astral Body and Luciferic Beings. The Nature of the Etheric Body (with Summary)
15. Aphorism 6: The "Guardian of the Threshold." Some Characteristics of Suprasensory Consciousness.
17. Aphorism 8: The Boundary between the Sensory and the Suprasensory Worlds.
18. Aphorism 9: On the Nature of the Spiritual Worlds.
19. Aphorism 10: Cosmic Beings of the Spiritual Worlds.
20. Aphorism 11: On the First Rudiments of the Physical Body.
21. Aphorism 12: The True "I" of the Human Being. (with summary and further Remarks)