"I like this book."
Translation:Lubię tę książkę.
Well, it is grammatically correct, but the word order is a bit awkward. In short sentences it may happen, that reflexive pronoun is at the very end (eg. "umyj się!" = "take a bath", "clean yourself up"). But in elaborated phrases that almost never happens to have a reflexive pronoun at the end (at least in normal speech - with poetry it is different). It is because the last word in the phrase is the most important one, and reflexive pronouns are not that much important, they only accompany the verb and pronoun (subject or object) just because the verb needs them.
It would be way more natural to say:
- "Podoba mi się ta książka" (if you want to stress that you are talking a bout the book), or
- "Ta książka mi się podoba" (if you want to bring out your attitude towards a defined book).