This document discusses the key elements required to form a valid contract: offer, acceptance, consideration, capacity to contract, and legality. An offer must be communicated to the other party and acceptance must be unconditional. Consideration means both parties receive some benefit. Advertisements are generally invitations to do business rather than binding offers. Silence does not constitute acceptance. A contract requires intent to create a legal obligation. Unsolicited goods do not create a binding agreement. An offer can be revoked before acceptance but consideration can make an offer irrevocable.