This study will evaluate patients with inflammatory forms of arthritis within the first year of onset. The study will attempt to clarify factors that may predict disease course such as evolution into rheumatoid arthritis (RA) or other chronic inflammatory arthropathies. Synovial biopsies and synovial fluid will be obtained to search for microbial agents and other initiating and modulating factors that may be most readily distinguished early in the disease and to determine the stage of disease at which certain immunologic and hormonal changes become evident. The study will also search for genetic and other features that may be associated with specific forms of inflammatory arthropathies that might predict the subsequent clinical disease course or response to different agents used in treatment of RA, Reiter's syndrome and other types of chronic inflammatory arthropathies.