You are a very open person who hides nothing from others. “I thought it would be hard to get information from him, but he was an open book.”

You understand their thoughts or intentions easily. "She's an open book; you can read her like a book, and she'll tell you exactly what's on her mind."

You are a mystery. It can also mean you are something that cannot be understood.

You can’t judge a person, experience, object, etc. just by what you see. “She doesn’t seem like she is the smartest, but you can’t judge a book by its cover.”

In my opinion/according to my beliefs/as far as I'm concerned. "The government's doing an awful job, in my book."

An outstanding or unusual achievement or event. "Last night's game was one for the record books!"

The process where you ensure that the amount of money coming in and going out matches up to what your records show.

You carefully examine the details, especially the T&Cs of something. "Before signing a contract, it's essential to read the fine print to avoid surprises."

You alter facts or figures dishonestly or illegally. "Their accountant was charged with cooking the books, and now he's in jail."

You have tried every possible way and method to do something. “He used every trick in the book until he finally got what he wanted.”

Punishing someone or calling them to account for their behaviour. "Bringing him to book is the only option to make him understand his actions are wrong."

Are beginning to study. “I never even cracked a book open in my literature class, but I still got an A.”

You disregard or ignore established rules or conventions."In times of crisis, sometimes you have to throw the rulebook out of the window and be flexible."