How to stop the book module defaulting to IE7 standards mode?
I suspect you may have visited the book page in IE, and selected compatibility mode once, and it is now being remembered.  Another possibility is that you have an internet zone rule (probably an intranet rule) that is forcing compatibility mode on.  Your IT department may be forcing this via a policy, too.

I have had some problems with just using the meta in the header of a page, and have been using this:

/**
 * Implements hook_html_head_alter().
 */
function MYTHEME_head_alter(&amp;$head_elements) {
  // disable IE compatability mode
  // see http://msdn.microsoft.com/en-us/library/cc288325(v=vs.85).aspx

  $head_elements['x_ua_compatible'] = array(
    '#type' =&gt; 'html_tag',
    '#tag' =&gt; 'meta',
    '#attributes' =&gt; array(
      'name' =&gt; 'X-UA-Compatible',
      'content' =&gt; 'IE=Edge,chrome=1',
    ),
  );

  $head_elements['x_ua_compatible']['#attached']['drupal_add_http_header'][] = 
    array('X-UA-Compatible', $head_elements['x_ua_compatible']['#attributes']['content']);
}


This adds the meta, so you can see it when you do a view source, and it also adds a proper HTTP header to disable it.

Just note that if this is being enforced via policy or IE settings, you may not be able to override it.