How do you say what kind of books are interested in spanish?

There are several ways to say "What kind of books are you interested in?" in Spanish, depending on the level of formality and the nuance you want to convey:

Formal:

* ¿Qué tipo de libros le interesan? (This is the most formal option, using the formal "usted".)

Informal:

* ¿Qué tipo de libros te interesan? (This uses the informal "tú".)

* ¿Qué clase de libros te gustan? (This is a more common and slightly less formal way of asking, focusing on liking rather than general interest.)

* ¿Qué libros te gustan? (This is the most informal and simple option, just asking what books you like.)

* ¿De qué tipo de libros te lees? (This translates to "What kind of books do you read?", implying interest through the action of reading.)

The best option depends on your context and relationship with the person you're talking to. For most casual conversations, "¿Qué tipo de libros te gustan?" or "¿Qué libros te gustan?" would be perfectly acceptable.