An object is any item you place on a page in your book. Photos, widgets (interactive media), shapes, text boxes, tables, and charts are examples of objects.
There are three kinds of objects:
An inline object is embedded in the text flow and moves with the text.
A floating object is fixed to a particular position on a page. You can drag floating objects anywhere on a page, and wrap text around them, or layer text or other objects over or behind them.
An anchored object is fixed to a particular position on a page, but it’s also attached to specific text (a word or paragraph, for example). If the text moves to another page, the object appears on the new page in the same position. An anchor marker indicates the text the object is attached to; you can drag the object or the marker anywhere on the page.
By default, objects you add in iBooks Author are either anchored or floating, but you can easily change an object from one kind to another.
Inline objects and most widgets (of any object type) always appear in both landscape and portrait orientation. Floating and anchored objects behave differently depending on the kind of template you use.
Landscape: Floating and anchored objects (besides widgets) are hidden when a reader rotates the device to portrait orientation. However, if you give an object a title or caption, or enable the object to be viewed larger, the object appears in portrait orientation as a thumbnail image, which the reader can tap or click to maximize the object.
Portrait: Floating and anchored objects always appear.