The function of legal research is to find out how previous courts have decided cases with similar fact patterns. One’s attorney (or a paralegal under their supervision) may review statutes, case law, and secondary authority before deciding how to proceed with your case. Since the law is based on precedent, case law with a similar fact pattern can give his or her attorney an idea of how things may play out in court. Likewise, a corporate lawyer may conduct legal research in order to determine whether a proposed new policy would expose the company to liability. This may include research into building codes, employment laws, or federal environmental regulations.
Public laws and private laws are different in the sense that the former includes laws that affect the public while the latter includes laws that affect one person or entity. Public laws, by definition, are those that affect the public generally, such as tax laws, laws relating to federal lands, laws relating to bankruptcy, and the like. Examples of public laws are Bankruptcy and Debt Law, Estate and Probate Law, Property Rights and Real Estate Law, Tax Law, and so on. Private laws, on the other hand, are those that affect only one person or entity or a small group of persons, granting them some special benefit not afforded to the public at large. The most common private laws are those dealing with immigration or naturalization; for instance, those allowing an individual or a family to enter the United States even though the immigration quota of that country has been met. An example of private law is the Immigration Law.