There's an H.P. Lovecraft tome I can't tell you much about as I found it far too long and gloomy to finish. It must have been in paperback print somewhen roughly around 1970.
My justification for 'far too long and gloomy…' is that the first several hundred of perhaps 700 pages 'merely' take our hero on an arduous trek through a barren, rocky mountainscape riddled with tunnels, punctuated only by meeting and defeating two or three monsters.
Crucially, he relies on dehydrated water not in gaseous but in tablet or pastille form — and it's the vague explanation for the chemistry of those tablets that interests me.
There's a quotation before the main text with the odd form This to be love: and I don't recall the definition which followed.
I have looked at various internet bibliographies but from Lovecraft's dozens of works, none has a title that's even vaguely familiar. I think I'm looking for two words; possibly three.
I have tried searching SE for sci-fi, horror and Story ID but the rest is too vague and 'Lovecraft' found too many hundred hits….