I have a relatively recent model iMac with a thin body, so there's no side panel or edge to which to attach anything. This holder attaches to the back with a 3M Command strip. I can fold it completely around to where it's not visible from the front of the computer, but when I swing it around, it can hold a document completely centered in the holder. I've only used it to hold single-page documents, but I believe the clip and the attachment is strong enough to hold multi-page documents with no issues.
Rating: [5 of 5 Stars!]