Best book series/method for learn English? (Searching for advices)

I already know English, but some of my friends asked me about the book series/method for learning English, so I wanted to ask you about it.

Explaind as u know​:face_with_hand_over_mouth::joy::joy::joy:

Just read what you love. I remember when I was learning English, I re-read my favorite Twilight books in English.

When it comes to helping your friends learn English, it’s great that you want to provide them with some guidance. While I don’t have a specific book series or method to recommend, I can share a personal anecdote.
I recently became obsessed with the GoT books. While they won’t directly teach English, they offer a unique way to immerse yourself in the language. The intricate storytelling and rich character development can actually be a fun way to improve vocabulary and comprehension.