The following explains the first two distinct stages on the path to nirvana.
Stream-enterer: The first direct insight into selflessness is often the most powerful because it's unlike anything you've ever experienced before. For a timeless moment (which may last just an instant), no one is there — that is, there's no trace of a separate self anywhere. A feeling of tremendous relief, often accompanied by joy and bliss, generally follows the experience: At last, you've had the insight you've been seeking for so long. At last, you've "entered the stream" of realization.
When you become a stream-enterer, you can never again believe that you're really a separate self that lives inside your head and looks through your eyes. Your experience forever eliminates this illusion. When you look within, you can't find a self anywhere. In everyday life, however, you may still feel like a separate somebody and may still get caught up by greed, anger, ignorance, and various other negative feelings and patterns. Fortunately, the stage of stream-enterer also brings an unshakable confidence and dedication to the Buddhist spiritual path, so you're motivated to keep deepening and refining your realization.
Once-returner: After you become a stream-enterer, your practice includes reminding yourself of your new realization of "no-self," as well as paying attention to the ways that you're still attached and your resistance to life as it unfolds. After a period of time in which your concentration gets even stronger and your mind becomes even more tranquil, you have another direct insight into no-self. (Remember, knowing this truth as a concept or memory is one thing, but experiencing it directly, beyond the conceptual mind, is something else entirely.)
This insight (essentially the same as the first but even stronger and clearer) brings a significant reduction in attachment and aversion and the suffering that accompanies these states of mind. For example, occasional irritation and preference replace hatred and greed, which no longer have any hold over the once-returner. Someone who reaches this stage has only one more rebirth before becoming completely enlightened — hence the name once-returner.
I hope this will provide you sufficient information to understand what you were looking for. And remember these stages are achievable for the modern man. One way I know how is through regular practice of meditation. Simply put I would say it is the recolonization that your mind (ego mind) and you are two different things, by your self.
"Eckhart Tolle" is some one who talks about this situation