At the core of every lawsuit is a mix of information—revealing documents that chronicle a party’s malfeasance, guarded memos that outline a lawyer’s trial strategy, fading memories that recall a jury’s key mistakes. Yet the law’s system for managing that information is still poorly understood. This Article makes new and better sense of that system. It begins with an original examination of five pieces of our civil information architecture—evidence tampering rules, automatic disclosure requirements, work product doctrine, peremptory challenge law, and bans on juror testimony—and compiles a novel study of how those doctrines intersect and overlap. It then fits these five doctrines into a creative rule typology, one built on the frame of “(in)valid (mis)information.” This typology charts our system’s most basic commitments—to accuracy, to adversarialism, and to procedural equality. But it also raises a critical question about the space between what our rules now require and what legal actors actually do. To help answer that question, this Article reaches out to an untapped social-science discipline: the rich and instructive field of Information Behavior (IB). This Article uses IB to shed new light on how our information rules function and where they still may fail. It also offers fresh and focused insight on the nature of information in civil litigation—from before a lawsuit opens until well after it ends.