Barbara Hand Clow was involved among others with Barbara Marciniak, and then went on, it seems, to channel and such on her own. Her works are different, no doubt.
I read the book a number of years ago (not in English); I don't have it around and so cannot look up anything beyond my memory, but going by what I remember of it, it is basically a typical New Age channeling with the disinformation from sources involved in uncritical channeling that one would expect. (Bringers of the Dawn was more the exception, not the rule, being unusually uncorrupted for a work of its type)
Going by my memory, which is a bit fuzzy since about 7 years or so have gone since I read it (back in more New Age-ish days, it being borrowed to me), I remember that much of the main narrative was by some "Satya" goddess of the Pleiadians who was described, in a New Age scale of dimensions (not corresponding to the densities of Ra and Cassiopaeans) as being in 5D. Other beings were "interviewed" as well, including (but not limited to) "the moon", some entity known as "Doctor Lizard", and (this channeled work adhering to the Sitchin-style ideas of there being a Nibiru and speaking not of the Lizzies but of some - in this case metallic - Annunaki) of the leader of the "Annunaki", who was in deep trouble (in very bad health, having supposedly failed to control humanity according to plan and causing instead self-destructive behavior) and really quite sorry about all the bad stuff having been done to humanity.
Another not-so-accurate idea that I remember being written about is the purported "Photon Belt". There was also some strange idea about odd versus even dimensions that I do not quite remember, but connected to it was the idea that 3D humanity was destined to go to 5D. On this idea of 3D humanity going to 5D, thinking of it in the scale of densities in the material around here, there is something at once funny and disquieting about those channelings that propose this. As noted in High Strangeness (2nd Ed., p375) by Laura:
High Strangeness (2nd Ed. said:
We have found similar explications of the "spiritual science" of the Cassiopaeans in the work of a few others--very few--Ra, Castaneda, Gurdjieff/Ouspensky, ancient Sufi teachings, ancient myths and legends, and we have an whole new segment of the puzzle that fits by virtue of numerous amazing correspondences, in the work of Boris Mouravieff. What is more, this material also contains added information that is startling in its implications.
Among those implications, which just happen to confirm some current observations, is the likelihood that this planet is going to have a rough ride not too many years down the road, including the idea that a lot of the human race may be checking out at that time. Quite a number of other "sources" are telling their followers that they are soon going to ascend to "the fifth dimension, skipping the fourth", and this is indeed the truth, though they don't fill in the details. Fifth density is where you go when you die.
Such a grand cosmic joke being pulled by 4D STS - of course, it will not be so funny for those who are invited to the dinner.
The near-destruction of humanity is not a failure of their control - it is a periodic feast.
EDIT: One thing I remember that, allegorically speaking - not regarding the details - the book by Clow seemed to get sort-of right is the idea that "Lucifer", which according to the C's are us - the human race - is a "higher being" trapped here. In a sense, this is correct in that humanity fell and now has to learn "the hard way" to graduate from this environment and its controllers.
ahahaha 
