Authors Andrea Bartz, Charles Graeber, and Kirk Wallace Johnson sued Anthropic for copyright infringement, alleging that pirated copies of their books had been used to train Claude (Bartz v. Anthropic). The complaint said Anthropic had obtained the works from piracy sources including Library Genesis (LibGen), the Pirate Library Mirror (PiLiMi), and Books3. Among the wave of suits over AI training data, this one turned on two questions: whether training itself is fair use, and whether obtaining pirated copies is a separate wrong.