How to find the Author Name using SP Client Context in SharePoint 2010?

Question

I am trying to find the Author Name(created by) for a given Item Id using the SP Client context in SharePoint 2010.

Below the code snippet

var ctx = new SP.ClientContext.get_current();

        //this.web = ctx.get_web().get_lists().getByTitle(;

        var query = new SP.CamlQuery();

        var queryStr = "<View><Query><Where><Eq><FieldRef Name=\'Series\' /><Value Type=\'Choice\'>Sample</Value></Eq></Where></Query></View>";

        alert( queryStr );

        query.viewXml = queryStr;

        var list = ctx.get_web().get_lists().getByTitle('PKS Podcasts');

        listItems = list.getItems(query);

        ctx.load(listItems);

        ctx.executeQueryAsync(Function.createDelegate(this, this.onSuccess), Function.createDelegate(this, this.onFail));

    }
    function onSuccess(sender, args) {      
          var listEnumerator = listItems.getEnumerator();
          while (listEnumerator.moveNext()) {
           alert("Item containing ‘announce’ found! \nTitle: " + listEnumerator.get_current().get_item("Author"));                      
          } 

    }
    function onFail(sender, args) {
        alert('failed to get list. Error:'+args.get_message());
    }       

But it is returning the object and not able to get the Author name...is there a way to find the same?

Answer 1

Solution moved from comment:

alert("Item containing ‘announce’ found! \nTitle: " + 
    listEnumerator.get_current().get_item("Author").get_lookupValue());