https://www.amazon.com/s?k=enneagram&ref=nb_sb_noss_1 searching ‘enneagram’ at amazon, and you can also search “gurdjieff ennegram’ for some books on
the ennegaram overall.
I came across the books on the enneagram of types at Amazon and was surprised and shocked/saddened by the proliferation of total crap on the subject. I am not exaggerating but stating a fact as my view: total crap.
The enneagram by itself was bad enough, the connection with the enneagram of types is an almost tragic emergence of a new superstition. It is not even a case where some insight might emerge by itself. Overall, the gravitation of Total Crap will cause everything to fall into shit.
Strangely, the path proposed by Gurdjieff will probably be total confusion from now on, forever. It will be impossible to sort out the growing confusion. Serves Gurdjieff right. But then the ghost out there doesn’t care and got what he wanted from Ouspensky, a global movement of unsuspecting suckers for an exoteric cattle round-up. The stuff in Ouspensky wasn’t a path anyway and has led nowhere after a century.
Gurdjieff by rejecting modernity, along with all the other gurus, cut himself off from the future. His promise of higher knowledge now meets dozens of mendacious money-grubbing books on the enneagram. In a way that is a fate for the symbology of the enneagram: it makes people so curious, yet unsatisfied, that someone will supply the rising demand.
This material will be a superstition of the future, but it won’t come to any result. People have tried many times to figure out the enneagram, but nothing ever happens because it is a form of idiocy.
The law of three and the law of seven, technically, are different. Someone still has a chance to explain them, but the enneagram version takes all of it a step further into imagination.
I am not aware of a single elucidation of the subject of the enneagram. If anyone could have provided it, it would have been Bennett. But his later books, e.g. Toward a New World, descend from the relative clarity of Dramatic Universe to the level of Gurdjieff at his basic unintelligent collation of materials that confuse all his students without any redress to explanation. Bennett knew better than to peddle the enneagram but he was caught up in the cult. In any case, as with all the other books on the subject, a close look shows that his books on the subject are interesting until he gets to the enneagram at which point he has nothing to say, a nine-term system, aha!