Just adding to this problem. I'm confused by Apple's documentation for PDFOutline. It says: "The index of the outline object is relative to its siblings and from the perspective of the parent of the outline object. The root outline object, and any outline object without a parent, has an index value of 0." So that suggests that Outline objects added to the root Outline should have a non-zero index. But, when I try to add the first child with an index of 1, I get an NSArray Beyond Bounds error.