1. Ich lese gerne Bücher There is a long list of possible translation for "gerne". In this context I would translate it as "to enjoy doing something" or "to like doing something": "I like / enjoy reading books." 2. Ich mag Bücher lesen. "Mögen" has also a long list of possible translations and "like" is one possibility. But in this phase I would translate it as "want" or "would like": "I want to read books." Example: Question: "Was magst du machen?" (What do you want to do?) Answer: "Ich mag Bücher lesen." (I want to read books) To express the same as in sentense 1), you might say: Ich mag es, Bücher zu lesen . (I like it to read books.) Another common expression is: - Ich mag Bücher. ("I like books" or "I am into books")

They literally translate to: 1. I read books with pleasure/gladly lese = read gerne = with pleasure/gladly 2. I like reading books Mag = like/enjoy lesen = reading So both are totally correct and can be used in a proper sentence :)