var book = {

 tarzan : { publisher: "Pub A", author: "Author A", pageCount: 300},
 "hidden universe" : { publisher: "Pub B", author: "Author B", pageCount: 1000},
 addBook : ....,

 removeBook : function(name) {
  this[name].name = name; //<-
  var temp = this[name];
  delete this[name];
  return temp;
 }

};