At its core this book is about loneliness and our inability to understand others and even ourselves. The pivotal character in this is, John Singer, a deaf-mute, whom the other four main characters have pinned their pent-up desires to be understood on, yet fail to reciprocate this, even worse, fail to even realize Singer needs to be heard, too.
Before meeting the others Singer had roomed 10 years with his friend, Spiros Antonapoulos, a morbidly obese deaf-mute whose personality changes after a bout of illness, and he ends up being sent to a mental asylum. Without his friend Singer has no one he can effectively communicate to, I say to because Spiros rarely communicates back or seems to care anything about Singer. It is a very lopsided friendship but one that Singer clearly depends on.
This is where I felt disenchanted with story. I struggled with this character's seeming intelligence yet unwillingness to seek out a better relationship for himself. I felt had he taught one of the others ASL they could've shared a true connection. But, then I realized this was the point. We've all had or are in relationships where we're not heard or understood yet we remain in them because we are convinced they provide something we need. Whether it's a bad marriage or a relationship with a "higher power" we stay trapped because we're scared to be alone and lonely. We don't want to stare into the abyss and realize that there is nothing waiting for us beyond our planet; there's no heaven or hell just cold empty space.