In this Essay, I argue that civil discovery rules compelling the production of private papers violate the Fourth Amendment’s prohibition against unreasonable searches. A “search” occurs when a government agent intrudes upon a sphere in which society recognizes “a reasonable expectation of privacy.” Implicit in this definition is an affinity for private papers such as letters and diaries. Creators of such media possess a reasonable expectation of privacy in their contents. Thus, when police seek to examine such documents to look for evidence of crime, they usually must obtain a search warrant. For the warrant to issue, the police must establish probable cause. Conversely, under the Federal Rules of Civil Procedure and parallel state provisions, all a litigant needs to do to “unlock the doors of discovery” is file a complaint endowed with “well-pleaded factual allegations” that “plausibly give rise to an entitlement to relief.” When this modest obligation is met, the Federal Rules direct courts to compel the production of any papers sought that are “relevant to the claim or defense of any party.” No detail is too intimate to shield it from scrutiny. Courts even routinely order the production of personal diaries. I assert that to pass constitutional muster such orders, like search warrants, must be premised on a showing of probable cause.