Oddly enough, the work of Emil FischerFischer, Emil (1852–1919) leading to the elucidation of the relative structures of the monosaccharidesMonosacharide(s) was only a part of his work that was recognized by the Nobel PrizeNobel Prize in 1902. By 1889, Fischer had begun to consider that the monosaccharides were stereoisomersStereoisomers of each other, and he set out the sixteen isomers predicted by the van’t Hoff model of the carbon atom. The arguments used by Fischer to derive a structure for glucoseGlucose still stand, over 100 years later, as one of the most impressive feats of chemical logic in the history of the discipline. The whole structure of his logical derivation of a structure for glucose appeared in two papers, published in 1891. These papers also contain the first publication of Fischer’s new projection formulas for what we now term stereogenicStereogenic centers. His arguments stand on three foundations: (1) the interrelationships between the monosaccharides, established by oxidation–reduction chemistry; (2) the molecular symmetry of the saccharic acidsSaccharic acids (and the alditols)Alditols; and (3) the application of the Kiliani-Fischer homologationKiliani-Fischer homologation (elongation) of aldopentosesAldopentoses, and the symmetry of those pentoses. The prelude to his work and Fischer’s analysis is presented.