Lucid dreaming - definition

A lucid dream is a dream in which one is aware that one is dreaming. The term was coined by the Dutch psychiatrist and writer Frederik (Willem) van Eeden (1860–1932).[1] In a lucid dream, the dreamer can actively participate in and manipulate imaginary experiences in the dream environment.Lucid dreams can seem real and vivid.[3] A lucid dream can begin in one of two ways. A dream-initiated lucid dream (DILD) starts as a normal dream, and the dreamer eventually concludes it is a dream, while a wake-initiated lucid dream (WILD) occurs when the dreamer goes from a normal waking state directly into a dream state, with no apparent lapse in consciousness.

Reality checks

Reality checks are very important because we want to be able to detect the time we're dreaming. The thing is that we need to pay attention to details.

Breathing, talking,.. - Can you breathe with sealed nose or talk with closed mouth?
Jumping,running,.. - Can you jump, then fly? Or, can you run extremely fast?
Reading - Anything specific about this daily activity?
Vision - Is the way you perceive world different? Is your picture distorted?
Time - Is everything right with the clocks? Are the people of the age they should be?
Strange elements - Anything you consider abnormal?

Techniques

Technique	Summary	Advantages	Disadvantages	Best for...	Rating
WBTB (Wake-Back-To-Bed)	Wake after some sleep and then return to bed.	Simple Can be very reliable, especially when used with other techniques	Disrupts sleep cycle	People who want to strengthen other techniques, or who wake up in the middle of the night anyway.	Green
Auto-suggestion	Let yourself genuinely believe that you'll become lucid—without intending to become lucid—so that you really will.	Simple	Less effective than some other techniques (such as MILD)	People who are highly susceptible to hypnosis or who don't have the energy for other techniques.	Green
MILD (Mnemonic Induction of Lucid Dreams)	Fall asleep while focused on your intention to remember that you are dreaming.	Simple	Can be boring	People with a good prospective memory (remembrance of future intentions).	Green
WILD (Wake-Initiation of Lucid Dreams)	Keep your consciousness while falling asleep and go straight into a dream.	Lets you truly induce lucid dreams at will	Can cause frightening experiences Can take long to master	People who want to reliably have lucid dreams.	Green
VILD (Visual Induction of Lucid Dreams)	By repetitive visualisation, incubate a dream in which you do a reality check.	Also lets you induce lucid dreams at will Works extremely well for some people...	...but not very well for others Visualizing can keep you awake	People who have good visualization skills.	Green/ yellow
CAT (Cycle Adjustment Technique)	Adjust your sleep cycle to encourage awareness during the latter part of your sleep.	Requires relatively little effort other than adjusting your sleep cycle Is very effective	Requires you to wake up early on some days You are only likely to get a lucid dream on every other day (though this could easily be more frequently than with other techniques)	People who have a very regular sleep cycle.	Green/ yellow

How long does it take to learn how to have lucid dreams?

This question varies from person to person. Usually from a couple of days to months of training. Some people have never paid any attention to dreams and dreaming whereas others have meditated and treated dreams as part of their "real" experiences.

Source: Wikipedia