Shiitake mushrooms are native to China where it has been cultivated for over 100 years, typically this mushroom is cultivated on the shii tree. The first written record of a shiitake can be traced to Wu Sang Kwuang, born during the Sung Dynasty 960-1127 A.D. Some documents, however, record the mushroom being eaten as early as 199 A.D.
Shiitake mushrooms are found in a variety of cultures & cuisines. Russia produces and consumes large amounts of shiitakes, although they are mostly sold pickled. Of course the shiitake has its home in Chinese & Japanese cuisines where you will find it in miso soup.
Shiitake mushrooms are commonly sold dried in preserved packages. All you need to do to re-hydrate them is to soak them in water prior to using. I prefer the fresh shiitakes myself, they have a better, more full-flavored taste.