Who was Ahithophel and why did Absalom send for him?

Ahithophel was a highly regarded counselor and advisor in ancient Israel, known for his wisdom and strategic insight. He was initially a loyal advisor to King David but later aligned himself with Absalom during Absalom's rebellion against David. Absalom sent for Ahithophel to gain his counsel in order to strengthen his claim to the throne and effectively undermine David's rule, believing that Ahithophel's advice would lend credibility and strategic advantage to his rebellion.