Well, that was very strange. In no way science fiction, it's more of a philosophical enquiry by means of a space-travel narrative and apparently brings in Gnostic ideas as well as some kind of Norse gods reference towards the end. It also depicts a descent from a kind of Eden into murderous darkness because after all "Humans are bastards." 
Somehow it is well ahead of the curve on issues of gender, with much discussion of the aspects of male and female, and one character who is genderfluid and has their own pronouns (in 1920!), and later on a caricature 'manly man' who appears to defy gravity by his balls.... I chuckled at this bit but that was about the only laugh after the first chapter or two as Maskull becomes more and more drawn into the long war between pleasure, duty, pain, and all the rest of the archetypes that I am sure litter this very peculiar narrative. 
But at least it isn't written in a false-archaic style such as William Hope Hodgson used to affect. That would have made it unreadable, and although I didn't want to spend more than a couple of days on it, it wasn't unreadable.