Albert Barnes Commentary 2 Samuel 13:1

"And it came to pass after this, that Absalom the son of David had a fair sister, whose name was Tamar; and Amnon the son of David loved her." — 2 Samuel 13:1 (ASV)

The history here, down to the end of 2 Samuel 23 (excepting a few particulars), is omitted in the Book of Chronicles.