What does the narrator mean by Only Gatsby man who gives his name to this book was exempt from my reactions?

The quote you're referring to is from F. Scott Fitzgerald's *The Great Gatsby*, and it reads: "Only Gatsby, who gives his name to this book, was exempt from my reactions."

Here's what the narrator (Nick Carraway) means:

* Gatsby's exemption: Nick is describing his overall detached and somewhat judgmental attitude towards the people he encounters in West Egg, including Gatsby. He observes their superficiality, their wealth, and their flaws. However, Gatsby is different.

* Gatsby's mystery: Gatsby is a figure shrouded in mystery. Nick is intrigued by him and finds himself drawn to his enigmatic nature. This intrigue overrides Nick's usual cynicism and judgment.

* Gatsby's influence: Gatsby's charisma and aura of the past somehow influence Nick. He's compelled to get closer to Gatsby and understand his story.

In essence, Nick is saying that Gatsby is the only character who transcends his usual emotional distance and judgment. This is because Gatsby represents something more than the other characters; he represents a yearning for the past, the pursuit of dreams, and the power of illusion.

This quote highlights Gatsby's unique position in the novel, setting him apart from the other characters and making him the central figure of the story.