I read this book right after reading Vance's Tales of the Dying Earth, and that may have helped a little: Vance is a beautiful user of language, and so is CAS, perhaps to an even greater degree. He was a poet who turned to pulp writing to support aged parents, and never stopped writing poetry in creating his pulp fiction.
A Door to Saturn is volume 2 of the 5 volume Night Shade complete collected works, so I guess its not for everyone in that there are cheaper collections of CAS's best work out there. But oh! the moments of beauty in every tale in the book, even in those "weaker" tales.
The best stories in the book are the titular "The Door to Saturn", with a superb opening sentence that not only packs a punch, but also contains so much information, despite a potential over-use of commas: "When Morghi, the high priest of the goddess Yhoundeh, together with twelve of his most ferocious and efficient underlings, came at morning twilight to seek the infamous heretic, Eibon, in his house of black gneiss on a headland above the northern main, they were surprised as well as disappointed to find him absent." And it only gets better from there, full of dark humour and dire consequences for all involved.
"A Rendezvous in Averoigne" is a chilling little vampire tale from when vampires were evil, and scary, and would dominate your will and drink your blood. "The Ghoul" is unforgettable, as is "The Good Embalmer": both are short tales with a big impact.
CAS tells a wonderfully descriptive parable in "The City of the Singing Flame". The possible meanings vary from reader to reader - is it about religion, money, drugs, obsession, or something else altogether.
"The Return of the Sorcerer" is a horror story full of boding dread and impending doom.
There are a host of other stories - 20 in all - all with endnotes containing discussion of the stories, usually by way of correspondence between CAS and HP Lovecraft. Sometimes this is perhaps a little too much of a glimpse at the man behind the curtain, but in a definitive collection of work I can certainly understand its place.
This is a superb collection of works, and should be more widely read.