Masquerade and Other Stories (POD):Born in Switzerland in 1878, Robert Walser worked as a bank clerk, a butler in a castle, and an inventor's assistant before discovering what William H. Gass calls his ''true profession.'' From 1899 until he was misdiagnosed a schizophrenic and hospitalized in 1933, Walser produced nine novels and more than a thousand short stories and prose pieces. Walser's contemporary admirers were few but well placed. They included Franz Kafka, Hermann Hesse,