This is a most interesting book. (= This is a very interesting book.) this is a most interesting book (đây là một cuốn sách hay lắm);
Compare: This is the most interesting book I have ever read. — This is a most interesting book. Ví dụ: It was the most interesting book that I have ever read. ( Đó là quyển sách thú vị nhất mà tôi đã từng đọc)