Plasma cell dyscrasias are common causes of peripheral neuropathy. Peri- pheral neuropathy may be the first manifestation of multiple myeloma, amyloidosis, or monoclonal gammopathy of undetermined significance (MGUS). Peripheral neuropathy occurs in more than one-half of patients with osteosclerotic myeloma. The hematologic disorders are such an important association with peripheral polyneuropathy that, for the last decade, we have obtained a metastatic bone survey and immunoelectrophoresis of serum and a 24-hour urine specimen on all patients older than 40 years with undiagnosed peripheral neuropathy. This textbook on polyneuropathies and plasma cell dyscrasia is welcome, because the subject is of considerable medical importance and because the authors are expert in these disorders. Kelly's studies have shown that a systematic search for monoclonal proteins in plasma and urine among patients with neuropathy of unknown cause increases diagnostic yield. Latov's studies have focused on the role of myelin associated glycoproteins (MAG) in the induction of neuropathy. Kyle, director of the Special Protein Laboratory at Mayo Clinic, brings a broad clinical and laboratory perspective and experi- ence. The timing of the textbook is just right, because there is much new information which needs to be summarized.