Title: Formalizing Mathematics-In Praxis: First Experiences with Isabelle/HOL Abstract: This talk is an overview of my first year of Isabelle/HOL, working within the ALEXANDRIA project at the University of Cambridge, as a pure mathematician with no prior formalization experience. I give a summary of our work so far and I comment on some of the early difficulties I encountered, as my goal is to point out some suggestions that could make Isabelle more practical for current and future users as well as to share with new users several technical and conceptual observations that might prove to be helpful in their early learning stages.