Interlocutory appeal from the district court's denial of defendants' pretrial joint motion to preclude the Government from relitigating certain issues under the Double Jeopardy Clause and from constructively amending the indictment is dismissed, and the case is remanded for further proceedings, where, because the district court's ruling is not a "collateral" order subject to immediate review under Cohen v. Beneficial Industrial Loan Corp. and was not otherwise a "final decision" under 28 U.S.C. section 1291, the appeals court lacks jurisdiction to consider the appeal.