Two resources for what it is, avoiding the scams, why NOT a living trust, and 3 reasons for having a living trust are below. The quick answer to what is a living trust is:
A living trust is one that is created by you to handle how your property will be passed to heirs and how property will be divided, etc. so that all happen according to your wishes. Naming one’s self as the Trustee during his or her lifetime ensures control of the trust and it’s assets while the creator of the trust is still living.
Three Reasons For Having A Living Trust (Estate Plan Law Blog)