The second edition of the Handbook has been thoroughly updated, influenced by the seven years of Processing being taught in classrooms, computer labs, and studios since the first edition. Every chapter has been revised, and added chapters introduce new ways to work with data and geometry. New “synthesis” chapters offer discussion and worked examples of such topics as sketching with code, modularity, and algorithms. Interviews have been added that cover a wider range of projects and history. “Extension” chapters are now offered online so they can be updated to keep pace with technological developments in such fields as computer vision and electronics.