Plaintiffs’ firms are private, for-profit law firms that represent individuals and groups seeking to redress injuries, commonly in the fields of workers’ rights, consumer rights, personal injury, medical malpractice, product liability, antitrust violations, and securities fraud. They can overlap with private public interest law firms (PPILFs), which are private, for-profit firms with a primary mission to assist underrepresented people or causes, rather than exclusively to make money and to dedicate at least a significant portion of their primary (not pro bono) caseload to matters that have some broad social, political, or economic impact, often focused on a particular topic or mission. This mission creates differences in billing practices and client selection. Some clients may be chosen with more emphasis on their need for the firm’s services and the cause their claim relates to, regardless of their ability to pay. Sliding scale fees, free work, attorney fee cases, and contingent fee cases are common. Deciding whether a particular law firm fits within the definition of a “plaintiffs’ firm” or “public interest law firm” is not always a simple task. An individual firm’s classification will require additional research into the firm’s overall philosophy, clients, and cases.