Adult 18+ sci-fi books

Shadow Walker

Treachery in Death

The Plea of Apollisian

Twinkle

Treachery in Death

Void Stalker

Swallowtail and Sword; The Scholar's Book of Story and Song

Memories of Ice

Empire of the Dead

And All the King's Men

The Testament of Tall Eagle

The Asbestos Society of Sinners, Detailing the Diversions of Dives and Others on the Playground of Pluto, with Some Broken Threads of Drop-Stitch History, Picked Up by a Newspaper Man in Hades and Woven Into a Stygian Nights' Entertainment

The Salarian Desert Game

Sleeping Jenny

Angelica Died

An Ancient Englishman: A.D. 1599-1906: Being the Strange Narrative of One Geoffrey Grenville, Elizabethan, Written by Himself, and Affirmed as Truth on the Word of His Friend, Rudolph Courtney, Esq., of Hadleigh Hall, Near Brighton, in the County of Sussex

Eaten Alive!

Desolation

Dreamwalker

The Fog Boggarts

Road to the Soul

Deadly Secrets

The Hunted

Eternally

Unbound

Lifeboats

The Caphenon

Mercy's Gift

The Dominion of Light

Earthlord