Summary judgment motions play an important role in business disputes; they can create settlement leverage, narrow trial issues or, if granted for an entire case, achieve a favorable judgment without a trial.  As its name suggests, a motion for summary judgment asks a court to “summarily” adjudicate a claim or lawsuit without the need for trial, based on a movant presenting evidence showing there are no “triable issues of material fact” to be decided. Whether a court will grant or deny a summary judgment motion depends on the evidence submitted by the parties.  Recently, the California Supreme Court clarified the role experts are permitted to play in this regard.  In Perry v. Bakewell Hawthorne, LLC, 2 Cal.5^th 536 (2017), a plaintiff claimed that stairs on defendant’s property were defective.  When defendant filed a motion for summary judgment attempting to show that the stairs were not defective, plaintiff submitted declarations from experts opining that the stairs were not compliant with building codes.  The experts, however, had not been designated by plaintiff, who missed the statutory deadline to designate them. The trial court sustained defendant’s objection to the declarations because plaintiff had failed to disclose the experts. The Court of Appeal affirmed the judgment in favor of defendant. The California Supreme Court also affirmed, noting that Code of Civil Procedure § 437c, subdivision (d) requires that declarations in summary judgment proceedings “set forth admissible evidence.” The Supreme Court stated:  “Therefore, we hold that when the court determines an expert opinion is inadmissible because disclosure requirements were not met, the opinion must be excluded from consideration at summary judgment if an objection is raised.”  Notably, this holding overruled two prior authorities that supported the admission of such expert evidence in a summary judgment motion.  Mann v. Cracchiolo, 38 Cal.3d 18 (1985) and Kennedy v. Modesto Hospital, 221 Cal.App.3d 575 (1990). The Perry case is significant in the context of business litigation for two reasons.  First, the consideration as to whether or when experts should be designated should take into account whether they may be needed to support or oppose a summary judgment motion.  Second, the case further exemplifies California’s move towards a more liberal approach to summary judgment, consistent with the 1992 and 1993 amendments to § 437c which liberalized summary judgment standards.