This book lists me as the author, but that doesn’t mean it is solely my book. Only through the implicit and direct contributions of dozens of people did the book come into existence. Without their support, inspiration, and collaboration, I would not have started or finished this long project. Writing a book is hard to begin and even harder to finish, which makes the help and involvement of others crucial.
First, I would like to thank all those who inspired me by showing the power of teaching and education. My dear Grandma Lubov Krivobok, a world-class chemistry teacher who continues to work with high school students in her late 80s, preparing them for high-ranked medical universities and academies; and my dear aunt, Oksana Semochkina, and uncle, Alexander Semochkin, both PhDs in mathematics, who dedicated themselves to raising the next generation of mathematicians and software engineers: you three showed me that true teaching is a craft and that if someone decides to share their knowledge, they must do so with complete dedication.
Second, I would like to thank those who supported me throughout this project: my lovely wife, Elena, and our two adorable but mischievous boys, Lev and Chris. This book was a sacrifice for all of us. We didn’t have a proper vacation. We could have spent much more time together. But we’ll catch up. The book helped me realize that family is even more important to me than I thought. I love you.