This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
In the types of breach thus far discussed, the party who breaks the contract has manifested his intention by word or deed to disregard the obligation of the contract, and no longer to recognize it as binding upon him. Breach may also exist where one party without repudiating the contract in any way, either omits performance, or tenders a performance which is not even a substantial performance of the obligation imposed upon him by the contract.1 The question of what constitutes such breach turns on the answer to the questions (1) what was the party, alleged to be in default, bound under the contract to do; and (2) what has he in fact done. The first question is primarily one of construction; the second, one of fact.