<p>There’s also the REA book. Both are notoriously riddled with errors, but I think you can request a correction sheet from Princeton Review.</p>
<p>You might take a look at “All the Mathematics You Missed: But Need to Know for Graduate School.” I haven’t heard it specifically recommended for the GRE subject test, but I’ve heard that it’s a very concise overview of the most important bits of the core subjects.</p>
<p>The largest single portion of the test is Calculus, and I remember reading a recommendation to just pick up Stewart or what have you and work on the “challenge” problems towards the end of each section problem set. The person recommending this said that these are close to the difficulty of the test’s calculus questions.</p>
<p>You mention your languages, and though the story may be different at Harvard, the language requirement is a joke at most schools. Most often, your competency test is to take as much time as you need to translate a page of mathematics with the help of a dictionary. If you can do that, you’re golden. They don’t care if you’re fluent. And, I think German, French, and Russian are usually the languages offered to chose from.</p>
<p>Hope this helps,
Joe</p>