Meaning: This sentence describes the person's positive emotional state after completing the book.
Choice of Words: "Felt" is the past tense of the verb "to feel", which means to experience an emotion or sensation. "Happy" is an adjective that describes a state of contentment or joy. "After" is a preposition that indicates a point in time following an event. "Reading" is the present participle of the verb "to read", which means to look at and understand written or printed words. "Book" is a collection of written or printed pages that tell a story or give information.