Gamma brainwaves occur during creative thinking and processing of memory and language and in many learning activities. These brainwaves are not present at all when a person is under anesthesia, but return as soon as the person becomes conscious again. Multiple scientific studies have shown gamma brainwave entrainment to be helpful for reducing distractibility, improving short-term memory, improving motor coordination, and relieving migraine headaches.

If you want the most results in the least amount of time, a well balanced approach is to listen to IQ Increase and Beta Relaxed Focus once or twice per day, and then use one of the 30 or 60 minute meditation tracks once during the day and again as you are going to sleep. That means a maximum of FOUR entrainment sessions per day. Trust me, that is a LOT of entrainment for your brain.

Given that brainwaves control and connect such a vast range of human experience from thought to feelings to actions, it is easy to see how the deliberate control of brainwaves can affect mood, behaviors, motivation, and even physical health. Brainwave entrainment is a safe, simple, and scientifically proven method for quickly guiding the brain into a beneficial brainwave frequency to facilitate healthy sleep, lower stress, heal emotional problems, and improve physical health.
Transparent Corp's Research Area is arguably the most comprehensive resource for collated brainwave entrainment research.   Update: the main research area on Transparent Corp's website is currently being updated, so it is offline.  However, you can still access their peer-reviewed research paper as a PDF here: “A Comprehensive Review of the Psychological Effects of Brainwave Entrainment“.

Unlike many traditional therapies for dealing with stress, anxiety, depression or cognitive impairment, entrainment does not require a focused effort from the person having the therapy, as the brain instinctively follows the frequency. This makes it a much more effective therapy for managing some of these challenging conditions, by automatically inducing a sense of relaxation and a reduction in negative physical and emotional patterns.
“Binaural beats are not very noticeable because the modulation depth (the difference between loud and quiet) is 3 db, a two-to-one ratio. (Isochronic tones and mono beats easily have 50 db difference between loud and quiet, which is a 100,00-to-1 ratio). This means that binaural beats are unlikely to produce an significant entrainment because they don’t activate the thalamus.”
You don’t have to run in order to get a runner’s high. All forms of exercise, including yoga and walking, can ease depression and anxiety by helping the brain release feel-good chemicals and by giving your body a chance to practice dealing with stress. You can go for a quick walk around the block, take the stairs up and down a few flights, or do some stretching exercises like head rolls and shoulder shrugs.
Taking five minutes to reflect on how you pulled through other stressful situations like your last breakup or when you switched jobs can help you reconnect with your resilient side. In the moment, it may feel as though you'll never get over your present problem, but when you look back, you realize that you felt similarly before and found a way to overcome it. If you're going through a divorce or recently lost a loved one, you also may want to seek out a support group: Research on grieving presented by the Center for the Advancement of Health in Washington, D.C., suggests that talking with peers is even more beneficial than one-on-one counseling in the initial months after a loss.
When tuning instruments that can produce sustained tones, beats can be readily recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible. As the two tones get further apart, their beat frequency starts to approach the range of human pitch perception[1], the beating starts to sound like a note, and a combination tone is produced. This combination tone can also be referred to as a missing fundamental, as the beat frequency of any two tones is equivalent to the frequency of their implied fundamental frequency.
The composer Alvin Lucier has written many pieces that feature interference beats as their main focus. Italian composer Giacinto Scelsi, whose style is grounded on microtonal oscillations of unisons, extensively explored the textural effects of interference beats, particularly in his late works such as the violin solos Xnoybis (1964) and L'âme ailée / L'âme ouverte (1973), which feature them prominently (note that Scelsi treated and notated each string of the instrument as a separate part, so that his violin solos are effectively quartets of one-strings, where different strings of the violin may be simultaneously playing the same note with microtonal shifts, so that the interference patterns are generated). Composer Phill Niblock's music is entirely based on beating caused by microtonal differences.
As to the second question raised in the above paragraph, audio with embedded binaural beats alters the electrochemical environment of the brain. This allows mind-consciousness to have different experiences. When the brain is entrained to lower frequencies and awareness is maintained, a unique state of consciousness emerges. This state is often referred to as hypnogogia "mind awake/body asleep."  

There's no doubt that brainwave entrainment audio is a great technology for anyone who is interested in encouraging altered states of consciousness and it certainly can help people to reach deeper states of relaxation than they might normally have access to. I myself will often listen to brainwave entrainment music in order to enhance my practice of meditation. But let’s keep a balanced perspective, put all the marketing hype to one side for a moment and acknowledge that there is no brainwave entrainment technology in this world that can make you meditate like a Zen monk “at the touch of a button”, despite what some might like you to believe. The mind is NOT a machine. It moves through various states of consciousness in an organic way and at a natural pace. We certainly can guide and accelerate that process with the use of brainwave entrainment audio, but we cannot control it with the same sort of specificity and immediacy as you might control the speed of the car you drive.

So if you are interested in using brainwave entrainment music in your own recording, do so with the knowledge that it can only help to improve the quality of your work. But please don’t feel as though your recordings will be insufficient without it (some people do worry about this - unnecessarily). My advice is that if you ever find yourself in a situation where the music you love the most is not available with brainwave entrainment frequencies, don’t ignore your intuition and discard that music. When you find that piece of music that brings your recording to life, go with it whether it has brainwave entrainment frequencies or not. The quality and feel of the music itself are the most important factors.
Whenever we become very relaxed and the usual chatter of the mind slows down a little bit, if we remain aware and do not slip into sleep or unconsciousness, we begin to perceive things that we had not noticed before. This is slightly different than the issue of “expectations” discussed previously, although a relationship to them can develop which will be discussed below. These have to do with the fact that in our typical state of consciousness our mind is racing so fast and so loud, and our body is so engaged with activity and physical tension, that we are unaware of some subtle perceptions that are there all the while, but which get buried beneath all the physical and mental noise.
Women worry more than men do. A study of 166 married couples who kept stress diaries for six weeks found that women feel stress more frequently than men because women tend to worry in a more global way. Whereas a man might fret about something actual and specific—such as the fact that he's just been passed over for a promotion—a woman will tend to worry abstractly about her job, her weight, plus the well-being of every member of her extended family. Keep your anxiety focused on real, immediate issues, and tune out imagined ones or those over which you have zero control, and you'll automatically reduce stress overload.
LEARNING OBJECTIVE • Exercise can be an effective component of a stress management program, and all types of exercise can be beneficial for stress management. Exercise programs consistent with the current recommendations to improve health can be prescribed to manage stress. Fitness professionals should recognize that it might be necessary to refer a client to a psychologist or other health care provider to help develop strategies for managing stressors that produce chronic and acute episodic stress.
With almost 100 years of research validating the effectiveness of brainwave entrainment, it’s no wonder why it’s used by thousands of people all over the world. What does the future entail in this exciting field? With the adoption of smartphones, virtual and augmented reality, and advancements in technology reducing the cost of EEG and other forms of biofeedback devices, the entrainment possibilities are endless.
Sound and light are the most popular methods to entrain the mind, yet there are a few other options in our toolbox. Using vibrational energy from sources such as magnets and electricity has been proven to help overcome addictions, depression, and even treat neurological disorders such as Parkinson’s. In this section, we cover these alternative forms of brainwave entrainment.
Binaural-beat perception originates in the inferior colliculus of the midbrain and the superior olivary complex of the brainstem, where auditory signals from each ear are integrated and precipitate electrical impulses along neural pathways through the reticular formation up the midbrain to the thalamus, auditory cortex, and other cortical regions.[6]
If brainwave entrainment leaves you with unwanted side-effects (see below) or discomfort, you’re probably encouraging a range of brainwaves that are already excessive in some area of your brain. The way around this is to get a brain map to see what your brain’s strengths and weaknesses are, and see what (if any) brainwaves could use some encouragement.