When the United Nations decided to declare 2025 as the International Year of Quantum Science and Technology, it was simply formalizing what was already common knowledge: That quantum mechanics is the most successful scientific theory of all time. This is because it not only explained our world throughout its spacetime extent ― from the Big Bang to the emergence of life on a suitable planet ― but also changed it through technology more than anything else in human history to date.

It was therefore expected that at some point this would also happen in our country, as it was already the norm in most European countries: To include in the curriculum of the Greek Lyceum ― specifically in the 3rd grade ― a basic introduction to the fundamental ideas of this top physical theory.

Given the above, this book was written with the fellow educator in mind who is called to teach this introduction and feels the need to have a book written especially for them. However, the book is also addressed to that special category of curious students every dedicated teacher would like to have in their classroom.

The first five chapters of the book cover the five topics of the curriculum ― blackbody radiation, photoelectric effect, Compton effect, wave-particle duality of matter, uncertainty principle ― and their goal is the substantial understanding of the related phenomena, with the solving of appropriate exercises being an integral part.

However, the last chapter has more of a tutorial character: It includes a brief Summary of the Basic Theory of each taught topic, followed by a suitable Self-Assessment Test. The chapter closes with a Comprehensive Test, while the answers to all tests are provided at the end of the book.

Our individual disagreements with the choices of the school program are presented where the relevant topic arises, but are also gathered in a special Afterword, along with our proposals for small realistic changes that would significantly improve the teaching effectiveness of the course.

In short: What we aimed for here is to be a useful book, with a strong focus on the needs of fellow educators.