A field or “practice area” of law refers to legal practice relevant to a particular type of law, or, more commonly, a particular industry or business. Most law relates to business, with a handful of exceptions. The largest exception is criminal law – the body of law relating to crimes. Criminal law involves litigation brought on behalf of the government (state or federal) against an individual, group or corporation, seeking to hold the latter accountable for the commission of crimes. Most lawyers in criminal law either represent the government (prosecutors, sometimes called District Attorneys, or, at the federal level, US Attorneys), or those charged with crimes (defense attorneys). Attorneys working as prosecutors generally work on salary for a local, state or federal government agency. Defense attorneys can be in private practice – paid either by their clients or by the government on behalf of indigent clients – or work for a government-funded public defender agency.
Civil law is often contrasted with criminal law, but the category is a little too broad for career exploration purposes. It refers to all legal disputes and relationships between and among non-governmental entities, as well as those with government acting in its non-prosecutorial mode. More helpful in understanding what lawyers do is the distinction made between transactional practice and litigation.
Lawyers categorize civil legal practice based on the type of law or the industry in which they work. So, for example, bankruptcy, intellectual property and personal injury each refer to areas of legal doctrine focusing on, respectively, financial failure, rights in ideas or intellectual production, and harm to individuals. They are independent of any particular industry or area of business. On the other hand, oil and gas law, admiralty law and entertainment law each involve a range of legal issues specific to particular industries.