Investigations into the nature of foxing (reddish-brown blemishes), found on paper from old prints, manuscripts, and even not-so-old books during the last sixty years have not resolved the disagreements about the cause or causes of the condition. Two schools of thought have each had reasonable basis for their hypothesis. One school places the blame for foxing on the presence of iron, or similar metals, either as a concentration of salts or as an actual speck or particle. The name foxing is derived from the color which is reminiscent of the color of iron rust. The second school recognized that paper from foxed spots was discolored and weakened much like cloth or paper that mildewed so they proposed fungal infection as the cause of foxing; the reddish-brown represented colored microbial metabolites. This study of paper decomposition included investigating foxed spots through optical micro-photographs, high resolution scanning electron photomicrographs, x-ray spectral analyses to determine what elements are present, and comparison of photographs taken of thin layer chromatographic separations of chemical components extracted from foxed spots and from naturally aged degraded paper.