Step 1: Understanding the Concept:
The question provides a jurisprudential statement about the fundamental purpose of the law of contract. This statement emphasizes the "expectation interest"—the idea that contract law's primary function is to fulfill the reasonable expectations created by a promise.
Step 2: Detailed Explanation:
This classic and widely quoted statement on the object of contract law is attributed to Sir William Anson, a renowned English jurist and author of the highly influential textbook, "Anson's Law of Contract." First published in 1879, this book has been a foundational text for law students for generations. Anson's perspective was that the law steps in to protect the expectation that a promise will be honored, thus ensuring predictability and trust in commercial and other dealings. The quote perfectly encapsulates this expectation-based view of contract law.
Step 3: Final Answer:
This statement is by Anson.