The keynote speeach entitled “Singularity” by Prof. Michele Lanza was given at the 9th IEEE Working Conference on Software Visualization (VISSOFT 2021). The VISSOFT IEEE Working Conference on Software Visualization continues the history of the ACM SOFTVIS Symposium on Software Visualization and the IEEE VISSOFT International Workshop on Visualizing Software for Understanding and Analysis. The conference focuses on visualization techniques that target aspects of software maintenance and evolution, program comprehension, reverse engineering, and reengineering, i.e., how visualization helps professionals to understand, analyze, test and evolve software.