I agree with Michael that your quote sounds basically like a definition on Ayn Rand's part, so my counter-question is also, is there something more specific you have in mind?
Anyways, since "The nature of nature is outside man's volition" I think I am right in assuming you would like to know more about the power of man, i.e. what is man able to do and what is outside of his potency. For example, I might assert that it is in my power (volition) to give a red rose on valentine's day to my partner or not (it is up to me to decide whether I want to or not), but it is not in my power to change the flow of water in a river (to make a
bad but plastic example). Others might think that nothing is subject to man's will and that is actually nature that determines man.
The question what "power" a man's volition has is generally referred to as the Free Will-debate. Which basically has many a different author contributing to it all positioning themselves on a dimension between hard-determinists (who believe that man has no power at all) and indeterminists (who believe that man has a Free Will and it is this will that makes the world go 'round) and yet others who position themselves in the middle and suppose that determinism and free will is actually compatible.
For a very good overview of the historical and contemporary arguments concerning Free Will, I'd suggest you check out the entry on Stanford's Encyclopedia of Philosophy by Timothy O'Connor or The Oxford Handbook of Free Will by Robert Kane (2002 (1st ed.) and 2011 (2nd ed.)).
I'd usually suggest the Wikipedia entry for Free Will, because it normally gives you a very good starting point of the general concepts. However, personally, I came to dislike it, because imho it is somehow biased. But since that is my personal opinion (and maybe word of advice for caution) I also suggest that: http://en.wikipedia.org/wiki/Free_will