Appellate jurisdiction generally extends only to final decisions — those ending the litigation on the merits and leaving nothing but execution of the judgment. The rule prevents piecemeal review, and its application produces a surprising number of dismissed appeals.

What is not final. An order resolving some claims but not others; an order granting summary judgment on liability with damages to be determined; an order dismissing a complaint with leave to amend; and a ruling on a motion that does not dispose of the case.

Certification of partial judgments. Where multiple claims or parties are involved, a court may direct entry of final judgment as to fewer than all, on an express determination that there is no just reason for delay. The certification must be explicit; reciting the formula without reasoning is often reversed for an improper certification.

Separate document. In systems requiring the judgment to be set out in a separate document, the appeal clock may not begin until that document is entered or a period has run. This rescues more late appeals than any other rule.

Post-judgment motions toll the appeal period, and an appeal filed while such a motion is pending may be held in abeyance rather than dismissed under modern rules — but the safest course remains to file after disposition.

When in doubt, file. A protective notice of appeal costs little; a missed deadline is jurisdictional.