Have you ever had a dream in which you realized that there within the dream you were, in fact, experiencing a dream?
This awakening of your inner consciousness in the dream is known as conscious dreaming or lucid dreaming. To be lucid simply means to be aware - and in this case, to be aware of the dream is act of lucid dreaming.
Most everyone has had a lucid dream at one point in their life or another. Most of the time, they happen without any conscious intent or effort to make it so. It simply seemingly happens on its own accord - one second you're existing in the dream world, oblivious to what's happening to you insofar as it being a dream, and the next moment you realize "My god, this world is in my head! I'm inside my own dream!"
Many confuse this realization of conscious awareness with another idea: dream control. But lucid dreaming and dream control are two separate feats. Certainly, one can lead to another, but by no means does it mean that having a lucid dream will result in being able to control the dream.
What most people really mean when they say they knew they were dreaming and took control of the dream is that they were able to influence the reality of the dream. This may be in the sense of deciding to fly or deciding to talk to someone who appears as soon as you intend for them too. But what about everything else in the dream? Who is controlling this? Who looks at the ground and decides to make each blade of grass? Who decided to put that building there? If you make a character appear, did you decide what color their shirt is? What about their smile?
As you can see, the element of who or what is making or controlling the dream is quite illusive. It's not as black and white as it seems at first!
Lucid dreaming offers a gateway into this area as well as many others that are fascinating to anyone who is interest in consciousness exploration. I encourage you to take a second look at your dreams - and how do you know this isn't a dream right now anyway?