Growing Mushrooms cultivation
In the meantime, I can suggest a few books that I've personally read and found to be very useful.  You might find useful the articles on Reishi and other mushrooms for medicinal purposes HERE

I've listed a definitive source of information and Bible for the Cultivator -  Paul Stamet's "Growing Gourmet and Medicinal Mushrooms" retails for $36.00 but, when available, AMAZON.COM sells it for $26.00 US!!!    A TEN DOLLAR SAVINGS.   

Growing Gourmet and Medicinal Mushrooms

After years of living in awe of the mysterious fungi known as mushrooms -- chefs, health enthusiasts, and home cooks alike can't get enough of these rich, delicate morsels. With updated production techniques for home and commercial cultivation, detailed growth parameters for 31 mushroom species, a trouble-shooting guide, and handy gardening tips, this revised and updated handbook will make your mycological landscapes the envy of the neighborhood.

"The book you are about to read is a milestone in the new awareness of mushrooms. THE MUSHROOM CULTIVATOR BY Paul Stamets and J.S. Chilton is easily the best source of information on growing mushrooms at home....The authors demystify the art of mushroom cultivation and put mastery of it within everyone's reach. If you have been searching for information on this topic, you will find to be all that you have been looking for and more.

How are the mushrooms grown!?!?! 

I've decided, based on my own research, to list several commonly used cultivation techniques.

I've never used any of the following methods but know they are used following much varied correspondence and research materials.  Confirmation of such techniques I've found within Paul Stamets, author of the mushroom cultivating Bible The Mushroom Cultivator  and
Growing Medicinal and Gourmet Mushrooms. 

Shiitake mushroom
As I stated at the opening page, the technique I've used and preach is that of R. Rush Wayne, Ph.D. with his Growing Mushrooms the Easy Way with Hydrogen Peroxide Vol. I.

Read about Dr. Wayne or visit his website to purchase, for immediate download, his wonderful PDF file on how to grow mushrooms using his Peroxide method.  The PDF file is also available in hard copy.

Visit Dr. Wayne's Non Sterile Cultivation site HERE!