As we all know photosynthesis is the most fundamental lift process on earth. Really it is the reaction of life, since all forms of life require energy for maintenance and propagation. The solar energy is captured by green plants and then transformed into stored chemical energy in the form of a wide variety of reduced carbon compounds. In addition photosynthesis stored this solar energy for millions of years in the form of organic fossils, which are now used as fuels. Really we are not going to follow the history of photosynthesis, but to follow, as far as possible, the role of algae in progress of photosynthesis research. Although photosynthesis has been intensively studied by scientists for hundreds of years, the mechanism of this process remained till to the middle of the twentieth century unknown. It should also be admitted that even now, we know very little about certain aspects of photosynthesis. Attempts are still going on. Using algae which could be easily and efficiently cultivated under controlled conditions, these aspects might be fully resolved. Our work will be presented in three successive parts (Eras) hoping to succeed in scanning, at least, the most leading experiments appreciating the historical role of algae in photosynthesis.