This guide maps the two federal regimes that govern people who advise others about securities and explains how a firm determines which one applies to each of its activities. It works through the adviser definition and its exceptions, the broker definition and the transaction-based compensation factor that dominates it, and the consequences of getting either wrong. It then covers the fiduciary standard derived from the antifraud provision, the disclosure architecture built around the brochure, custody, marketing and performance presentation, recordkeeping including electronic communications, and supervision. Separate parts address private fund advisers, the federal and state allocation of registration authority, the examination process from selection through deficiency letter, enforcement forum and remedies after recent decisions, and the events that trigger a fresh registration analysis.