This introductory paper provides an overview of four contributions on the epistemological functions of mathematical symbolism as it emerged in Arabic and European treatises on algebra. The evolution towards symbolic algebra was a long and difficult process in which many obstacles had to be overcome. Three of these obstacles, related to the circulation and adoption of symbolism, are highlighted in this special volume: 1) the transition of material practices of algebraic calculation to discursive practices and text production, 2) the transition (...) from manuscript production to printed works involving material limitations of typefaces, and 3) the transition of algebraic symbolism from a system of notation and representation to a tool of mathematical analysis. This paper will conclude with the observation that the whole development towards symbolization can be considered an obstacle by itself in the sense of ‘epistemic obstacles’ as used by Brousseau. (shrink)