Oho. It got a cover page? Naisu. Very naisu.
However, despite all that, it's less of a cosmic horror story than you'd think, and becomes more of a creation myth and history of the early Galaxy…including how good old Homo Sapiens figured into it. That said, boy howdy are some parts creepy. Fascinating read, but there are some bits easier to take seriously than others. Plus, it's filled with Lovecraft-style purple prose.
Music is what I'd use for a certain race's leitmotif, once you reach them. Seriously, read this book. It puts all the mishandling of Abeloth in a much better place, somehow, and even reworks the Ones into a decent concept.