How do I turn this:

<a class="link">
   <p class="paragraph">This is some text</p>
   <p class="paragraph">This is some more text</p>
   <p class="paragraph">And some more</p>
</a>

into this:

<a class="link">
   This is some text This is some more text And some more
</a>

with jQuery. I tried using append and merge but I just can't figure it out.

• javascript
• jquery
• merge
• append

Since the text method returns the text content of an element and it's descendants, you can just use that:

var link = $("a.link");
link.text(link.text());​​​​​​​​​

From the docs:

Get the combined text contents of each element in the set of matched elements, including their descendants.

Here's a working example.

Update (see comments)

In the case that this needs to apply to multiple .link elements, you can use each:

$("a.link").each(function() {
    $(this).text($(this).text()); 
});

This will work:

$("a.link").text(function(i,text){
    return text;
});

And yet another way (not tested):

// you can optionally filter to
// only p elements too with
// .children("p")
$("a.link").children().contents().unwrap();

Here's another variation of the second:

$("a.link p").contents().unwrap();

Edit: Just a note for clarity:
All of these solutions work on multiple elements. The first solution is a relatively uncommon syntax that can be used on most jQuery setter functions. It runs the callback on each matched element and sets the value of the property/attribute to the value returned from the callback.

try this

    $(document).ready(function(){
      var concatText = "";

      $("p.paragraph").each(function(){
       concatText = concatText + " " + $(this).text() 
      });

        $("a.link").html(concatText);
​     });​