Honestly, what can I say? this is the clearest and most comprehensive esoteric cosmology I have come into contact with throughout my time digging into these topics. I have no way of proving the statements in this book absolutely for myself or to anyone else (at least until I try developing supersensible consciousness and doing spiritual research myself), but that's not the point. This is the results of Steiner's own spiritual research, put out with the intent of familiarizing others with what he feels they will need to effectively expand their own consciousnesses. He does not expect you to accept his outline of spiritual and cosmic evolution as blind dogma, but rather to use the methods he outlines (in this work and especially in others like "How To Know Higher Worlds") To find and experience the truth for yourself. He provides information on his perceptions of the spiritual realms to give you a solid foundation to start with working your way back into the world of spirit and understanding the grand processes at play. Along with that, after my own reading and research into spirituality and esoterica, I have to say that Steiner's cosmology ties together everything I have learned, from many different sources, both ancient and contemporary, into one system that just makes an unbelievable amount of sense. I mean this both in terms of spiritual principles, and in terms of satisfyingly explaining the holes and mysteries that exist within our modern scientific-materialist view of the world, evolution, and history. When it comes to getting into cosmology and esoterica, outside of just the inner work (though the inner work is what matters most), this is one of the first books I'd recommend, even with how dense it is, and even with the fact that the overview style of the book skips alot of the nuances that are revealed when Steiner goes more in depth on one particular topic, as I think that was a necessary choice to provide an effective and efficient overview