"For man's only weapon is courage that flinches not from the gates of Hell itself, and against such not even the legions of Hell can stand." Kane, a knight-errant born as a Puritan, has only one vanity - pride that no one has ever questioned his courage. "A hunger in his soul drove him on and on, an urge to right all wrongs, protect all weaker things, avenge all crimes against right and justice."
My thanks to the publishers, who have assembled EVERYTHING, including unpublished material (not completed upon Howard's death) fleshed out by Ramsey Campbell, who did a good job. Campbell's introduction spells out, for each such story, who wrote which bits.
"Skulls in the Stars" - On the road to Torkertown, Kane is warned off the shortest route across the moors; a fiend has slain every traveler to pass that way for the last year. Kane takes this as a sign that another task has come his way.
"The Right Hand of Doom" - The necromancer may have deserved death, but Kane had only contempt for his betrayer, the magician's only 'friend' who sold him to the law. Not a good idea to cross a magician who has courage and nothing left to lose, waiting in the condemned cell at Torkertown.
"Red Shadows" - After comforting a dying rape victim, Kane commits himself to tracking down Le Loup and his men. The trail leads from France to Africa, ending with Kane's first meeting and alliance with N'Longa (in case you wondered how they became blood brothers). Don't be put off by N'Longa's poor command of English; when he puts aside his pride in his knowledge of the alien tongue and drops into river dialect, that should clear up any misconceptions about Howard's treatment of his character.
"Rattle of Bones" - Kane, passing through the Black Forest, stays the night at the Cleft Skull Tavern (English translation), meeting Gaston, a flamboyant fellow traveler who seems familiar.
"The Castle of the Devil" (Campbell collaboration) - John Silent, an English mercenary moving on to his next job, meets with Kane in the Black Forest, to learn that Kane cut down a boy from the local Baron's gibbet. As his castle - the Castle of the Devil - is nearby, Kane has a feeling that he will be called upon to ease another evil man of his life...
"Death's Black Riders" - A fragment, concerning a mysterious apparition encountered by Kane in his travels.
"The Moon of Skulls" - Sir John Taferal, upon his death in a duel with Kane, confessed that he had sold his young cousin Marylin to a Barbary rover, faking her death, in an attempt to become the heir of Lord Hildred Taferal. Kane, having rid the world of one Taferal, took on the job of restoring another, tracing her to Negari, ancient city of evil repute, lost colony of Atlantis.
"The One Black Stain: Sir Thomas Doughty, executed at St. Julian's Bay, 1578" - Poem. Solomon Kane, alone of all Francis Drake's men, has the courage to say, "Worthy of death he well may be, but the court ye held was a mockery..."
"Blades of the Brotherhood" - The Fishhawk and his fellow pirates set upon a ship in the Caribbean carrying the daughter of one of Kane's old friends. The trail has led him to an English manor, whose master respects no one and nothing, not even the victor in his latest duel, Jack Hollinster, who stopped at first blood only at a magistrate's orders.
"The Hills of the Dead" - N'Longa's initial gift to Kane - the cat-headed staff - ever afterwards travels with him.
"Hawk of Basti" (Campbell collaboration) - Jeremy Hawk, an old acquaintance from Kane's seafaring days with Grenville, survived shipwreck on the African coast only to stumble across the unknown civilization of Basti. Having set himself up as a god-king, he has been overthrown, and seeks a return to power.
"The Return of Sir Richard Grenville" - Poem. Upon being wakened in the middle of a jungle night by a ghostly warning, Kane isn't one to let wonder get in the way of survival.
"Wings in the Night" - Coming upon the ruins of an African village, Kane learns the truth behind the ancient legends of harpies. He's actually at a serious disadvantage against his winged enemies here.
"The Footfalls Within" - As part of this story, we learn much more about the cat-headed staff and its history, courtesy of one of a party of slavers who capture Kane. That was their first mistake - the second was to open up a sealed tomb deep in the wilderness. (No chance to make a third mistake after that.)
"The Children of Asshur" (Campbell collaboration) - Kane stumbles across a lost civilization (Assyrian, this time). Compare with Howard's "The Voice of El-Lil" if the culture interests you.
"Solomon Kane's Homecoming" - Short poem, relating Kane's return to his hometown after many years' absence.