Epigenetics 101 - Evolution Unraveled, #4

Epigenetics. Does it solve the question of Nature vs. Nurture? Epigenetics is the study of how environmental factors and behavior can modify how your genes function and how cells regulate gene activity without changing the DNA sequence. Few other technical scientific topics have recently captivated the public's interest like epigenetics has. The "epigenetic revolution" and claims that epigenetics undermines our knowledge of evolution are frequently discussed in headlines.
What exactly is epigenetics then? How does it operate? Why is it important? And is it the future of personalized healthcare?