by the book

US /baɪ ðə bʊk/
UK /baɪ ðə bʊk/
"by the book" picture
1.

secondo le regole, alla lettera

strictly according to the rules or established procedures

:
We have to do everything by the book to avoid any legal issues.
Dobbiamo fare tutto secondo le regole per evitare problemi legali.
The manager always runs the department strictly by the book.
Il manager gestisce sempre il reparto strettamente secondo le regole.