Who is Klaus Baudelaire from The Reptile Room and what is their importance?

Klaus is the middle child of the three Baudelaire siblings. He is twelve years old, exceptionally bright, and a voracious reader. One of Klaus' greatest strengths is ability to research problems thoroughly and pour through complicated books with ease. He has an extensive vocabulary, and he is often better read than the adults in the story.

In The Reptile Room, his talent for research comes into play when the Baudelaires must figure out a way to get out of their predicament with Count Olaf, and Klaus works with his sisters to find a resolution to their problem. Klaus does his best to watch out for Sunny and keep her safe.