This is the 2822nd most frequent Korean word.
읽을
"To read" (modifying form).
Here, '읽을' is used as a descriptive form before a noun, indicating 'a book to read'.
나는 새로운 책을 읽을 계획이 있어요.
I plan to read a new book.
In this case, '읽을' is functioning to describe the value of reading the book.
그 책은 읽을 가치가 있어요.
That book is worth reading.
Here, '읽을' describes the act of reading that is intended for readers by the author.