In Microsoft Corp. v. Baker, 137 S. Ct. 1702 (U.S. 2017) (No. 15-457), the US Supreme Court held that appellate review does not exist for a voluntary dismissal with prejudice of individual plaintiffs’ claims which purports to reserve the right to revive the dismissed claims should the court of appeals reverse the denial of class certification.  The district court denied class certification, and plaintiffs unsuccessfully sought Rule 23(f) permission to appeal.  Rather than pursue their individual claims to judgment, plaintiffs stipulated to a voluntary dismissal of all claims with prejudice, but reserved the right to revive their claims should the court of appeals reverse the denial of certification.  The US Supreme Court held that the voluntary dismissal did not qualify as a final appealable order under Section 1291.  In reaching this conclusion, the Court observed that the denial of class certification was not appealable as a collateral order, even where it provided a “death knell” to the litigation.  The Court also noted that Rule 23(f) permitted discretionary appeals of class certification denials.  With that background in mind, the Court concluded that only final orders resolving the entire controversy are appealable under Section 1291.  Plaintiffs’ “voluntary-dismissal tactic” violated these principles and invited protracted litigation and piecemeal appeals, the vices addressed in the final judgment rule.  Three justices concurred in the result, but opined that the Court’s conclusion was better grounded on Article III of the Constitution.  In particular, the concurrence posits that there must be an actual controversy at all stages of review, and reversal of the class certification denial would not rightly revive any claims on the merits.