Two special sessions entitled “50 Years of Circuits, Systems & Signals: A Session in Honor of Prof. Sanjit K. Mitra (Parts I and II) were presented at the 50th IEEE International Symposium on Circuits & Systems held at Baltimore, Maryland on May 28-31, 2017. Nine papers by authors from Brazil, India, Italy, Singapore, and USA were presented in these two sessions. Prof. Mitra was also recognized as a pioneer in the area of circuits & systems and presented a talk in the special session “Pioneers of Circuits & Systems II” at the same conference.