to stop doing sth because you no longer believe you will be successful or will find a solution :
The police have closed the book on the case (= they have stopped trying to solve it) .
to stop doing sth because you no longer believe you will be successful or will find a solution :
The police have closed the book on the case (= they have stopped trying to solve it) .
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005