What Is A "Prozbul?"

Our Sedra discusses the canceling of debts in the upcoming Shmita (7th) year. Mishna Shevi'it states that when Hillel the Elder (circa 100 CE) saw that wealthy people were refraining from loaning money to the needy during the Shemita year (a Torah prohibition), he enacted the "Prozbul," a device designed so that debts would not be cancelled & people would once again agree to loan money to one another. In essence, debts are transferred to a Bet Din, which is allowed to collect them even during Shmita. "Prozbul" comprises the Aramaic words: "Pruz buli ubuti," which translates as "an advantage to the rich & the poor." The prozbul benefited the rich by securing their loans & helped the poor by enabling them to borrow money even with a Shmita year approaching. Two valid witnesses sign the Prozbul, which is usually administered by the Rav of the Bet Knesset. The Prozbul can only be utilized when Shmita is rabbinic; when the majority of Jews live in Israel (very soon!) and Shmita is a Biblical law it may not be used.