Gamma brainwave states are the most rapid in frequency. Gamma has long been considered the brainwave that is able to link and process information from all parts of the brain. It is the frequency that brings with it the ability to process large amounts of information in relatively small amounts of time. Think of generating more Gamma activity as getting a processor upgrade for your brain.
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“.
I have never been more creative, productive, more loving to all people nor have I ever been happier in my life. All the wisdom I have found in my pursuit of happiness was somewhere in my intellect. Now it is a part of me. I am using it. I now consider myself a model for younger people to let them see how it is possible to function and be everything they’ve wanted to be. I just celebrated my 85th birthday and I am as young as when I was 25. Thank you for giving me the gift of my true self.
Both brainwave entrainment and neurofeedback deal with brainwaves, but the similarity stops there. Entrainment pushes your whole brain into a pre-determined state, while neurofeedback teaches you how to move specific parts of your brain on your own. It is the differeence between forcing the brain into a given position, and skills building so you can move it there yourself.