Mushrooms are one of the few ingredients that can be used equally fresh or dried. In fact, dried mushrooms often possess more intense flavors. Moisture evaporates during the drying process, and because mushrooms are comprised of mostly water, the end result is a concentration of flavor.
Prior to purchasing dried mushrooms, smell them if you can–they should possess a rich aroma. You should also choose darker colored varieties, because they possess more flavor. Select mushrooms without tiny pinholes, because that usually means that insects have been living there.