Summary judgment in federal courts has been widely regarded as an initially underused procedural device that was revitalized by the 1986 Supreme Court trilogy of Celotex, Anderson, and Matsushita. Some recent commentators believe summary judgment activity has expanded to the point that it threatens the right to trial. We examined summary judgment practice in six federal district courts during six time periods over 25 years (1975–2000), extracting information on summary judgment practice from 15,000 docket sheets in random samples of terminated cases. We found that when we controlled for changes over time in the types of cases being filed, the likelihood that a case contained one or more motions for summary judgment increased before the Supreme Court trilogy, from approximately 12 percent in 1975 to 17 percent in 1986, and has remained fairly steady at approximately 19 percent since that time. The increase prior to the 1986 trilogy and the modest changes subsequent to the trilogy would be unexpected by many legal commentators. Although summary judgment motions have increased over this 25-year period, this increase reflects, at least in part, increased filings of civil rights cases, which have always experienced a high rate of summary judgment motions. Surprisingly, no statistically significant changes over time were found in the outcome of defendants’ or plaintiffs’ summary judgment motions, again after controlling for differences across courts and types of cases. These findings call into question the interpretation that the trilogy led to expansive increases in summary judgment. Our analysis suggests, instead, that changes in civil rules and federal case-management practices prior to the trilogy may have been more important in bringing about changes in summary judgment practice.