The Diary of Science and Technology is a memorial work of those who have had a catalytic impact on the creation of our modern civilization, a civilization with great potential and prospects for development but also with latent self-destructive properties. The protagonists of this technological culture deserve to remain in the memory of the older generation or to become known to the younger generation because through their acquaintance one comes into contact again with significant moments of Science and Technology, bright and dark, but also with the human side of their contributors. Its diary format allows easy contact with them on a daily basis. By flipping through the diary, one can see every day or any day of the year, who was born and who died over time from 1200 to the present, in a period of 800 years during which modern science and technology were formed and shaped. The concise biographical notes and expressive sketches that adorn the work seek to give a lightning-fast image of their personality and work. The large number, by international standards, of the included pioneers (2500 personalities compared to 1000-1500 at most, found in international biographical dictionaries of registered scientists in the established "clinical" alphabetical way, while there are no corresponding Greek dictionaries at all) and the unique number of original sketches of them (1400), constitute a conscious effort to promote those people who, while contributing catalytically to the creation of modern civilization, remain practically unknown to the general public due to the lack of responsible information about the value, importance, and quality of their work, as well as the diversity of their personality. As the reader will discover, this work required from the authors a seven-year persistent and multifaceted effort, it is a human diary, very human. Day by day, through its pages, the discoveries, inventions, explorations, excavations, ideas, theories, and fantasies of those who shaped a space much broader than the established space of the exact sciences, medicine, and technology emerge. Along with all those traditionally characterized as scientists and technologists, there are explorers who opened the way of knowledge with their physical presence in the struggle for the conquest of the unknown (then it was the deserts of Africa and Arabia, now it is the deserts of the Moon and Mars), archaeologists, educators, sociologists, and philosophers of science, writers who either started as scientists or influenced science with their imagination or original thinking about related subjects that they developed in depth in their literary work, even film directors who projected scientific imagination to the general public. They are all nothing but planetary travelers in a world that remains essentially unknown and inexplicable, externally and internally. The work aspires to be an essential aid for both the specialized scientist and the high school student, as well as for every modern thinking individual.