The publication of the third edition of Henry M. Hart, Jr.'s and Herbert Wechsler's The Federal Courts and the Federal System is a trebly welcome event: It reminds us that Hart and Wechsler is a partnership whose impact on American law has been no less consequential than that of Lincoln and Herndon, or Langdell and Ames, or even the two Hands. It invites us to think again about the enduring conundrums of federal structure and judicial role that have defined our constitutional experience for the two centuries since the establishment of the federal courts. And it offers assurance, as the federal courts enter their third century, that those who will serve in and on those courts in coming decades will be prepared to address the old conundrums afresh and to fashion new ones.