Mrs. Falik brought this action in April, 1962, in the District Court for the Eastern District of New York to remove a tax lien of the United States as a cloud on the title to her home at Woodmere, Long Island. The lien was for withholding and social security taxes due from two corporations, of which the Commissioner of Internal Revenue had found her to have been a responsible officer, see Internal Revenue Code of 1954, Â§Â§ 3102, 3403, 6672; Mrs. Falik alleged that this finding was erroneous. The United States made a motion to dismiss for want of jurisdiction, amplified by an accompanying affidavit which spoke of sovereign immunity and the bar against injunctive or declaratory tax relief; Judge Dooling denied the motion, 206 F. Supp. 181 (1962). Two and a half years later the Government made a second motion to dismiss for want of jurisdiction or other appropriate relief, citing decisions in other districts contrary to Judge Doolings; the motion contained a request that, in the event of denial, the judge should grant a certificate for an interlocutory appeal under 28 U.S.C. Â§ 1292(b). Judge Dooling denied the motion but granted the certificate. Recognizing that the issue was one of importance in the administration of the revenue laws, on which district courts have differed; that this difference was due in some measure to our having accepted an argument of the Government in Pipola v. Chicco, 274 F.2d 909 (2 Cir. 1960), which, at the Governments urging, we branded as erroneous in United States v. OConnor, 291 F.2d 520 (2 Cir. 1961); that failure to allow an interlocutory appeal followed by a victory by the Government on the merits might moot the issue that we ought to determine; and that a reversal would "materially advance the ultimate termination of the litigation," we granted leave for an interlocutory appeal.