Ex parte Lange was a United States Supreme Court case that dealt with the issue of copyright infringement. The case involved a dispute between two photographers, Lange and White, over the ownership of a photograph. Lange had taken a photograph of a group of people and had registered it with the Copyright Office. White had then taken a copy of the photograph and sold it without Lange's permission. The Supreme Court held that Lange was entitled to copyright protection for his photograph. The Court reasoned that the Copyright Act of 1870 gave authors the exclusive right to reproduce their works. The Court also held that the act did not require the author to register the work with the Copyright Office in order to receive protection. Therefore, Lange was entitled to copyright protection for his photograph, even though he had not registered it with the Copyright Office. The Court's decision in Ex parte Lange established that authors are entitled to copyright protection for their works, even if they have not registered them with the Copyright Office. This decision has been cited in numerous subsequent cases and has become an important precedent in copyright law.

In Ex Parte Lange, the Supreme Court was tasked with determining whether a state court had jurisdiction to issue an injunction against a defendant who had been found guilty of criminal libel. The majority opinion held that the state court did not have such authority because it would be in violation of the First Amendment's protection for freedom of speech and press. Justice Field dissented from this decision, arguing that while he agreed with the majority's interpretation of constitutional law, he believed that states should have some power to protect their citizens from malicious or false statements made by individuals. He argued that if there were no legal recourse available to those affected by such statements then they could suffer irreparable harm without any means for redressal. Furthermore, Justice Field noted that many other countries allowed similar injunctions as part of their civil laws and thus it seemed reasonable for states to do so as well in order to ensure justice is served when necessary.