Restatements state and explain case law for different broad legal topics, presenting rules of law with analysis. Appendices note court cases that have cited the restatement. Restatements are a highly regarded persuasive authority, and their rules may even be adopted as law by a particular jurisdiction.
Another series also published by the American Law Insitute, Principles of the Law, is intended more to help reform the law than to explain it. These titles recommend how the law in an area should develop.
It takes a long time for the text of a Restatement to be updated, as the many experts involved in its adoption create and review drafts. When a new Restatement comes out, it will have a new edition indication (e.g., Restatement of Torts vs, Restatement of Torts 2d). The ALI publication list can help you determine which edition is the most recent for a particular topic area, especially as some subjects are broken into smaller components.
The appendices noting court cases that have cited the Restatement are updated. In print, this is done through a combination of new volumes and pocket parts/softbound supplementation to update each individual title. In addition, a separate softbound supplement, Interim Case Citations to the Restatements of the Law, updates all Restatements.
Updates to electronic resources are integrated in the database.