I was truly captivated by Oskar Schell's world - especially his fears and inventions. Although Oskar is never officially "diagnosed", he reminded me of children I have known who had Asperger's syndrome. His brutal honesty and awkward attempts to socialize with others were charmingly painful.
The cast of characters Oskar meets while on his search for the lock are a veritable cross-section of New York citizens. Through them, he slowly begins to trust again. Through Oskar, they slowly begin to heal from the brutality of 9/11.
The sub-plot involving Oskar's grandparents is sad and unpredictable. My heart broke watching them try to love each other, and fail miserably. You can't help but have your heart broken by the end of this book, but you will turn the last page with your faith in mankind intact.
I found the freestyle grammar and dialogue of Extremely Loud and Incredibly Close : A Novel to be a little off-putting and confusing, in what was otherwise a five-star novel.