What does the cryptic crossword clue "Book of 'Cats' rewritten (4)" mean?

The definition is "Book". The wordplay uses an anagram. anagram of 'CATS' = ACTS; definition: "Book" The answer is ACTS.

Book of 'Cats' rewritten (4)

Daily Mail Cryptic #16953 | 23 Down | 2022-10-25 flower