American Law Reports began life as a selective case reporter to compete with West's National Reporter System. They lost the battle, and have stopped printing cases. What remains from the original publication are the Annotations.
An ALR Annotation is a kind of super-annotation. In addition to long lists of primary legal materials from many juristdicitons, an ALR Annotation contains an essay about a narrow area of law. It will tell you how different jurrisdictions have dealt with that issue.
If you can find an ALR Annoation on your topic, then you will be well on your way.
Print ALRs have a variety of updating formats, but for the most part rely one pocket parts.
WARNING: Has your annotation been Supplemented OR Superceded?
Supplemented means there is a more recent annotation that has additional information so you need to look at both of them.
Superceded means that this annotation should no longer be used as there is a more recent annotation that has completely revised the topic.
Legal Research in a Nutshell, pp. 88-91.