This Article uses the example of free and open-source software licenses to show that granting authors relatively strong control over the modification of their work can increase rather than impede both the creation of future work and the variety of that work. Such licenses show that form agreements that enable authors to condition use of their work on the terms that matter most to them may give authors the incentive and assurance they need to produce work and make it available to others. Such licenses may therefore increase both the amount of expression available for use and the variety of that expression, even if enforcement limits the freedom of downstream users. These facts give reason to oppose recent decisions that make license terms harder to enforce through preliminary or permanent injunctive relief.