Aguilar

We granted review in this cause to clarify the law that courts must apply in ruling on motions for summary judgment, both in actions generally and specifically in antitrust actions for unlawful conspiracy.

I

This is an antitrust action arising from a complaint filed by Theresa Aguilar on behalf of herself and all of the other, by her estimate, 24 million retail consumers of California Air Resources Board, or CARB, gasoline —collectively, Aguilar—against Atlantic Richfield Company, Chevron Corporation, Exxon Corporation, Mobil Oil Corporation, Union Oil Company of California (later succeeded by 76 Products Company), Shell Oil Company, Texaco Refining and Marketing, Inc., Tosco Corporation, and Ultramar Inc.—collectively, the petroleum companies.

In conducting our review, we have scrutinized facts that are many and complex. The motions for summary judgment with which we are concerned produced a voluminous record, which fills more than 18,400 pages. They arose out of extensive discovery, which yielded, according to one tally, more than 100 depositions, 1,500 interrogatories, 135 requests for admissions, 900 requests for the production of documents, and 500,000 pages of…