A Force thought link was a telepathic link formed between two Force-sensitive individuals, allowing them to send thoughts into each others heads. It was a very effective means of communication, but somewhat disconcerting, and requiring mental discipline enough from both people to be able to tell which thoughts are theirs and which are the other person's, as according to testimony, the brain is not automatically able to tell the difference between them. Once formed, the link was absolutely unbreakable, but formation of the link required strong emotional attachment, and as a result, it was seldom formed by Jedi, and at certain points in the Order's history, the existence of this ability was all but forgotten.