Learn Spanish (Latin America): ¡Qué increíble! Ese libro es genial.

When Qué is followed directly by an adjective like increíble, it translates to "How" in English to form an exclamation. If it were followed by a noun instead, it would translate to "What a" (for example, ¡Qué libro! means "What a book!").

Why is it Ese libro and not Eso libro?

Ese is the masculine singular word for "that" when it comes right before a masculine noun like libro. You only use eso when you are referring to a general idea, a situation, or an unidentified object where the gender is unknown.

Why do we use es instead of está for "is great"?

We use es (from the verb ser) because being "great" is treated as a core characteristic or lasting quality of the book, rather than a temporary state, condition, or location.

Does the word genial change if we describe a feminine noun?

No, adjectives that end in a consonant like -l (such as genial or fácil) stay exactly the same for both masculine and feminine nouns. However, if you talk about multiple books, you do add -es to make it plural: Esos libros son geniales.