"He will never write this book."
Translation:Nigdy nie napisze tej książki.
I know in polish we can remove a Person but... This sentence have more sense with He
Omitting 3rd person pronoun isn't that common as others, but still, in real life you have context. If you were just talking about John and his attempts to write a book, there's absolutely no need to mention John/He in every sentence. He's known from the context.