know (something) like the palm of (one's) hand

know (something) like the palm of (one's) hand

To be extremely familiar with a particular subject, place, or piece of media. I've read this book so many times that I know it like the palm of my hand at this point. You should ask Samantha for directions—she knows this town like the palm of her hand.
See also: hand, know, like, of, palm
Farlex Dictionary of Idioms.

know someone or something like the palm of one's hand

 and know someone or something like the back of one's hand; know someone or something like a book
to know someone or something very well. Of course I know John. I know him like the back of my hand. I know him like a book.
See also: hand, know, like, of, palm
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • know (something) like the back of (one's) hand
  • know something like the back of your hand
  • know backwards and forwards and know forwards and backwards
  • know (something) backwards and forwards
  • know like a book, to
  • have a familiar ring
  • in a familiar way
  • get used to (someone or something)
  • familiar
  • familiar with (someone or something)