This document discusses the differences between formal and informal procedures in administrative law. It begins by introducing formal procedures like adjudication and rulemaking, which resemble court procedures. However, it notes most administrative decisions are made informally. It then distinguishes formal procedures, which are more legalistic and constrained, from informal ones where administrators have more discretion. Examples of informal procedures include advisory opinions and memoranda. The document discusses how formal procedures are generally required for adjudication, while rulemaking can be informal. It analyzes several Supreme Court cases that address these issues.