This is epic novel writing.
Like most Simmons books, the detail is astonishing: you'll feel like an expert in 1920s mountain climbing, among other things, and Simmons knows how to pace things so the details never stop the story.
Climbing Mount Everest, we learn, was grueling beyond the imagination of most of us armchair adventurers. Even after supplemental oxygen was introduced, there's a reason all pre-WWII expeditions failed to summit, the reason being that the mountaintop is a frozen, wind-lashed hell. Simmons pits four climbers against a larger, far better armed party determined to stop them from finding a lost climber's body and the secret the dead man was carrying. The history of mountaineering is told in the buildup to a deadly cat and mouse game in a realm where humans need every bit of stamina and grit just to stay alive, and yet must also fight for their lives.
Those wanting to learn about the yeti will not find a lot of detail, but the subject is pivotal at two points. To keep from spoiling it, I won't say whether Simmons' novel presents the metohkangmi as real animals.
My only moment of disappointment was in the end result of the larger geopolitical story that frames the deadly chase on Everest. Again, trying to avoid spoiling the experience, I'll just say that the good guys would have used their secret information long before they did, an odd mistake by an author who works so much history into his novels.
That was one bad moment in a superb book, though. If you are interested in tackling a long and unique novel with some cryptozoological bits, The Abominable (which is, itself, heavy enough to anchor a climbing rope or clobber a yeti with), you won't be disappointed.