"A cycle of ten lectures given at the Hague from 20 to 29 March 1913”.
Previous ed.: published as The effect of occult development upon the self and the sheaths of man. London : Rudolf Steiner Publishing, 1945.
The effects of spiritual development by Rudolf Steiner. ISBN 0854403191. Published by Rudolf Steiner Press in 1978. Publication and catalogue information, links to buy online and reader comments.