A lawsuit is a civil action filed by a plaintiff (the person who brings the suit) against a defendant (the person who is being sued). A lawsuit can be for money or for some other remedy that might include specific things (called equitable relief) such as telling the defendant to do something or to stop doing something. A lawsuit may be heard by a judge or by a jury.

If a lawsuit is filed, the next step is to gather evidence that proves the defendant’s liability for the damages claimed by the plaintiff. In some cases, like a slip and fall on someone else’s property, this could mean gathering medical records and finding an expert willing to testify that the person who fell was injured by the defendant’s negligence. In other cases, such as a class-action lawsuit against a bank that has illegally charged millions of people, this might mean collecting information from all the affected customers.

Once the evidence is collected, the case enters a pre-trial phase called “discovery.” This is when parties gather facts from each other and non-parties who might know information about the case. It can include depositions where a party or witness is asked questions under oath and interrogatories, written sets of questions that the plaintiff or his lawyer can submit to the defendant and that the defendant must answer.

Before a case goes to trial, the defendant must be formally served with papers that say that there is a lawsuit against them. This is usually done by hiring a professional process server to hand-deliver the papers.