1. Where one of the parties to a contract entirely fails to perform his obligation the other may repudiate it and he will be discharged from further performance. He may also claim for any loss he has suffered.

2. Two forms of breach:
a) Substantial failure of performance.
b) Renunciation before or after the time for performance arrives.

3. If the breach is fundamental, the aggrieved party is entitled to repudiate.
Failure to deliver one in a series of installments will not amount to this.

4. Where one party renounces his obligations before it's due or renders performance impossible by his own act, he is said to have committed an 'anticipatory' breach, which is actionable in English law.