The first chapter briefly summarizes the substantive law of when the trial court must instruct the injury in a criminal trial sua sponte, that is, on its own motion. The second chapter provides a practical, quick-reference checklist of instructions the trial court must give sua sponte in felony jury trials. The third chapter discusses what some judges think are the most common instructional errors made in criminal cases. These errors, not limited to sua sponte instructions, pertain to defendant testimony when adverse inference must be drawn, flight after crime, principals, aiding and abetting, implied malice, defendant's "pinpoint" instruction, the instruction that proof need not show the exact time of crime, and verdict based on unlawful acts. Tables listing statutes, jury instructions, and cases are provided.