An unauthorized entry onto a second-floor apartment’s private balcony with the requisite criminal intent constitutes burglary. A second floor balcony was only accessible from inside the apartment and was surrounded by a railing. The resident was awakened to find the defendant standing on the outside of the balcony with his hands gripping the top of the railing and his shoes protruding underneath. He was convicted of residential burglary based on a jury instruction that a building’s outer boundary includes the area inside a balcony that is attached to an inhabited dwelling. The Court of Appeal reversed for instructional error. The California Supreme Court reversed. The common law, on which the statutory crime of burglary is based, protected against the breaking and entering of a dwelling, which encompassed any structure within the curtilage or courtyard surrounding the house and used in connection with the house. Whenever a private residential apartment and its balcony are on the second floor or higher, and the balcony is designed to only be entered from the apartment, it is part of the apartment. The railing of the balcony marks the apartment’s outer boundary and the slightest crossing of that boundary is an entry for the purposes of the burglary statute. The court disapproved dictum in People v. Valencia (2002) 28 Cal.4th 1, 11, fn. 5 to the effect that an unenclosed balcony could not reasonably be viewed as marking a building’s outer boundary. The railing of the balcony marks the apartment’s outer boundary and the slightest crossing of that boundary is an entry for the purposes of the burglary statute. While the jury instruction was incorrect because it was overbroad, there was no resulting prejudice and a properly instructed jury would not have reached a different verdict.