Know like the palm of hand!

There are like three idioms a little hit different which mean quite the same thing. They are Know someone or something like the palm of one's hand, Know someone or something like the back of one's hand and know like a book.

They all mean to know something or someone very well!

For example: I have lived in Paris for 5 years and you can be pretty sure I know this town like the back of my hand.

I know my parents like I know the palm of my hand.

Tery knows cooking like a book.

Easy, isn't it?! :)