Restatements of the Law are produced by the American Law Institute, a group of scholars and practitioners who are elected for their expertise. The early Restatements provided concise statements of common law in an attempt to impose some order on a growing body of court decisions. Later Restatements attempt to state what the law will be or should be. They are highly influential and are often adopted as law by the courts.
The restatements consist of sections sequenced as follows:
1. The rule itself, often called the "black letter rule."
2. Comments discussing the meaning of the rule and the reasoning behind it.
3. Illustrations which are short hypotheticals showing how the rule is applied.
4. Reporter's Notes covering the history of the rule and references.
Finding Restatements on Contracts
There are two series: The Restatement of the Law of Contracts and The Restatement 2d of the Law of Contracts.
Restatement of the law, second--contracts 2d : as adopted and promulgated by the American Law Institute at Washington, D.C., May 17, 1979. by 
From the Law Library Home Page, go to Law Databases and select HeinOnline. Click on American Law Institute Library, then Restatements of the Law. Then drill down to the book you want to look at.
At Westlaw Precision, enter REST-CONTR in the search box. This will lead you to a search box for the first and second restatements.
At Lexis+, choose Secondary Materials, then navigate to Restatements, then Contracts.
Corbin on Contracts by Farnsworth on Contracts 4th ed by A treatise on the law of contracts by