The following line is from an article in the June 2015 issue of Science magazine.
Readers of Sacks know he is no stranger to writing about himself, having previously written several books detailing his encounters with patients displaying unusual neurological conditions.
Here, can "he" be considered the subject of the participial phrase ("having previously written..."), in which case this would not be a dangling participle; or, is it really "readers" that is the subject of the participial phrase, in which case this would be a dangling participle?