A home buying contract is the written agreement between the seller and the purchaser to transfer ownership of the property from the seller to the latter. The contract is a legally binding agreement for sale and is drawn up in two identical documents, one which must be signed by seller and the other which must be signed by the purchaser. Once both copies have been signed by their respective parties and exchanged via solicitors (which is known as the exchange of contracts) both parties are legally committed to the agreement.