The Wellmans, a father and son team, actually began writing this fusion of genres in the late 1960s, publishing it as a series of short stories in The Magazine of Fantasy and Science Fiction. A few months ago, however, Titan Books (who have really been championing the sci-fi field for the last few years) collected the Wellman's short stories and published them in a complete paper back collection, a collection I'm happy to recommend to not only fans of either Sir. Arthur Conan Doyle's characters or H.G. Wells' alien invasion scenario, but to all fans of sci-fi. One would think the melding of the two stories would yield an absurd, incongruous amalgamation, but the Wellmans have done an outstanding job of creating a storyline that triumphs on its own while at the same time never ignoring the debt to the men whom without their story couldn't exist.
The two have plucked the characters from Doyle's world and deposited them into Wells' end of the world, keeping Holmes and Watson untouched while modifying Wells' story rather significantly (though not disrespectfully). It opens with the titular character purchasing an odd crystal egg from an antiques dealer. A strange trait of this rare item has him showing the sphere to his scientist friend Challenger. When the two look into the crystal egg, they see not their reflections, but a spherical view into an alien landscape, a landscape they quickly deduce is Mars.
Though baffling, this gift of extraplanetary sight seems rather innocuous until the two spy movement in the glass. There are creatures on Mars, creatures that bare little resemblance to humans. And soon after one of these Martians locks eyes with Holmes across the gulf of space, astronomers around the world start noting that a series of cylindrical objects have been seen launching from the surface of the red planet.
From here the story falls more in line with Wells' original War of the Worlds. The Martians land and quickly exert their dominance over mankind, but instead of simply retelling the rest of Wells' narrative with the simple inclusion of Holmes, we're treated to a version of the familiar story that is thrown off axis by the inspired invention of this crystal egg. It gives the detective and his friends unique insight into the lives of the Martians, which is something the invaders are soon aware of as it becomes clear that they'd like to retrieve the important artifact.
I'll not spoil how it all comes together in the end, but suffice to say it's a wonderful updating of the original story. The Wellman's could have easily made an entertaining twist on the familiar with the invention of the crystal egg give (which gives new meaning, motivation, and understanding to the beings from beyond the stars) alone, but they've utilized it in unison with what we've come to expect from Holmes to create a story that has more going on than just the detective trying to figure out how to fight a bunch of alien tripods; which is likely what you'd expect from the book going off the title alone.
The characters are constantly trying to figure out what's going on, as opposed to the original proxies to Wells' story who were merely trying to survive. Not only is it an interesting bit of detective work, but said work brings about a bevy of concepts that should spark the imagination of sci-fi fans. The resulting chimera of the two fictional staples ends up being one of the most satisfying reads I've had in a while. You'd do well to check it out.