The Case of the Cosmological Killer, by Stephanie Osborn
I have reviewed all four of the books contained in the Omnibus separately on Amazon; they are paired. 1&2 should be read together, as should 3&4. Get the Omnibus, it's REALLY the way to go. Setup: Brilliant scientist Dr. Skye Chadwick is working with brilliant scientist ideas and technology, and has achieved a breakthrough: a portal to alternate realities. And there are a LOT of alternate realities. There are so many that they need some way to make sure that they are tracking the same world consistently; so, they need a test subject. ENTER: Sherlock Holmes. They discover that in one particular world, Holmes exists as a real person, and has near-identical existence with the character found in literature. Since many of the team are fans, they decide to use him as the focus of the viewing. And, ALMOST by accident, bring him to our world. It's only ALMOST by accident because Dr. Chadwick is a former cop, and the scene they view is Reichenbach Falls, and as Moria...