A legal opinion decides a case, creates precedent, provides learning material, triggers analysis, exposition and speculation, and informs both the legislature and the public. Practicing lawyers read court opinions when they are involved in the case, when researching a specific point of law, and when reading to broaden professional knowledge. A discussion of principles covering the use and content of both brief or memorandum decisions and full opinions examines the conflicting demands for speed and thoroughness in the judicial system. Thus trial court decisions, written in cases tried without a jury and addressed to involved lawyers and litigants, must be responsive to rules requiring explicit findings of fact and conclusions of law. They must also be written with the awareness that their law-declaring function is secondary to their dispute-resolving and review-facilitating functions. Supreme (or last resort) court opinions are written for the public and other courts, more as a literary exposition than a letter and should not dwell on the particulars of the case. Rather, they should place the issues and their resolution in a general legal context. Time constraints for trying criminal cases imposed by the Speedy Trial Act and the Nonpublication Rule resulted in writing of short opinions, of no opinions when a case was not precedent setting (particularly noticeable on the appellate level), and also curbed formal publication of opinions. Federal Courts of Appeal have adopted a plan for opinion publication and citation rules. Groups examining citation of unpublished opinions include the Advisory Council for Appellate Justice, the American Bar Association (ABA) Commission on Standards of Judicial Administration, and the ABA Lawyer's Conference Committee on Federal Courts and Judiciary. Seven footnotes are appended.