Spoiler alert: the Witch totally dies at the end, thanks to Dorothy's fire-safety training and a handy bucket of water. Given that we've all seen the 1939 movie, are we surprised by the ending of Maguire's novel? Well, yes. Maguire spends the entire novel building up Elphaba's character and flipping everything we think we know about her on its head. By the time we reach the end, we're hoping that, like so many other events, Elphaba's death won't be what it seems.
In an interview, Maguire described Elphaba as his "hero" and even expressed some admiration for the movie version of her, one of the scariest characters of all time: "She always tells the truth. In the movie, the Wicked Witch might be scary, but she never lies." (source)
Where is the maniacal and supremely wicked witch here? Well, as Wicked answers it, that shrieking maniac is just one facet of the actual person that is Elphaba. Wicked effectively reveals the iconic antagonist, the Wicked Witch of the West, to be a sympathetic, misunderstood protagonist.
The murder doesn't play out exactly the way it does in the movie. The scene is much more drawn out, Dorothy hasn't been kidnapped per se, and there's no army of green-faced dudes in Russian-looking fur hats (political statement?) hanging around shouting "Hail, Dorothy" when it's all over. But the murder is still a murder, and (unlike in the musical) Elphaba is decidedly dead at the end of the book. While we may have cheered at the Witch's movie death, we mourn Elphaba's.