TYPES OF CONTRACTS:
AS TO ACCEPTANCE
BILATERAL CONTRACT -- exchange of mutual promises -- each party is both promisee and promisor
UNILATERAL CONTRACT -- acceptance by performance -- the offeror requests performance rather than a promise, the offeror-promissor promises to pay upon the completion of the requested act by the promisee. Once the act is completed, the contract is formed.
Only two situations are unilateral --> (1) where the offeror indicates that completion of performance is the only manner of acceptance, or (2) where there is an offer to the public, such as a reward, which so clearly contemplates acceptance by performance rather than a promise.
Most contracts are bilateral --> unless clearly indicated otherwise by the language or circumstances, all offers are doubtful or indifferent offers, which means that they may be accepted by promising or beginning performance.