Andreas Ioannou Kassetas (1944-2015) studied physics at the University of Athens at the undergraduate level and in Paris at the postgraduate level, while teaching for many years in Private Secondary Education as well as in teacher training seminars, having also intense social and trade union activity.He was an author, co-author, or translator of numerous books, participated with presentations in many physics and science education conferences, wrote articles in various newspapers and magazines, while maintaining his own website (users.sch.gr/kassetas/). Believing in the importance of creating cognitive structures in students, with this book he attempted to organize the teaching of physics based on its concepts, at a level that would follow the initial formal teaching approach.

He balanced between the charm of ideas and the need for their application in everyday practice, without hesitating to make the necessary concessions but also proceeding with the conflicts that he believed should take place. He successfully used his unique sense of humor and self-critical disposition in his teaching, through which he conveyed many more things to his students beyond the knowledge of the content of physics. He refused to think in terms of black and white, believing in a multifaceted reality with infinite intermediate shades. He was a sui generis personality who will remain unforgettable to those who had the fortune to know him.