Hey there! Thank you for choosing my book. When I was just starting to learn programming in school, I did not understand so well how big this world is. We have big opportunities and little time. Every day is a competition in which you win or lose. We get our "human" label according our victories, and when we lose, we try again the next day. This book is a victory for me. It pushes me to win in the upcoming days. I'm behind this book, and all the people who have supported me during the whole writing process are by my side. A very big thank you goes to my mother, Gohar Mikaelyan, who motivated me to write and finish this book; to my sister Nelly, who helped me with the translation of the book; and to Anna and Melania, as well. I want to thank to all my friends and, most importantly, my father, Karen Khachatryan, who gave me the chance to enter the digital world when I was 10 years old by giving me my first computer. I would like to express very warm thanks to the Packt Publishing staff—in particular, Reshma Raman, Pooja Mhapsekar, Taabish Khan, and Amey Varangaonkar—for helping and supporting me all this time.