The first Doc Savage/Shadow team-up was in DC Comics, in a 1988 four-part crossover, "The Conflagration Man." It didn't exactly set the world on fire, nor did subsequent comic book team-ups. Now we have the first official book version. I'm unfamiliar with Will Murray's "Wild Adventures" of Doc and his Amazing Five, but he does a superb job of imitating the pulp style. The repetitions are deliberate, the tin ear is actually perfectly tuned. As others have mentioned, he even shifts styles between the solo Doc portions and the solo Shadow portions of the story, imitating Walter Gibson quite well. The only misstep (other than, I think, an overuse of Doc's subsconscious trilling) is his continual belief that "sepia" means "black," rather than reddish-brown.
The story uses Doc as a means of, essentially, delving into some of the continuity issues of the early Shadow stories. I think Murray plays scrupulously fair. The story is set in the autumn of 1933, and, except for some foreshadowing (heh), sticks to the pulp world that Lester Dent and Walter Gibson had created up to that point. It explains -- no spoilers here -- why the Shadow stopped using the identity of George Clarendon (an alter ego that I remember really puzzled me when I read the paperback reprint of "The Death Tower" around 1970). There are a few nice metatextual touches, like a reference to the "monk's hood" version of The Shadow featured on some early pulp covers.
The story is not a world-threatening adventure; not a great deal is at stake, and the super-villain is interesting because, throughout, he's not quite infallible--and he turns out to be a legitimate former foe of The Shadow, although I was unaware of him. All in all, well done.
One interesting facet that Murray makes clear without making too much of it is that Doc Savage's assistants are men of very high abilities, physical and mental, while The Shadow is essentially dealing with very ordinary people whose main characteristics are courage and total devotion to the will of their mysterious master.
I should mention that Murray does a fine job of referencing the workings of early-30s technology, and I like references like one character using a "Continental style" phone where the receiver and mouthpiece are connected.
The cover is all right -- it does present a scene from the book, but Doc is presented in his usual ripped-shirt cover appearance even though he's not that way in the scene, and there's something off about The Shadow's left arm.