The Mouseion of Alexandria and its library were considered as one of the great archetypes for modern civilization. During antiquity, vast numbers of scientists, scholars, philosophers, writers, artists and students have dreamed to join this blessed spot where all human knowledge, wisdom and books had been collected. In this place, the learned men of the Mouseion became able to conquest every field of culture. During the third and second centuries B.C. Alexandria became the residence of some of the brightest scientists and the center for the development of practical technology. Among the generations of scientists who succeeded in the Mouseion and its Library and worked there for long hours to study and scrutinize, some examples have emerged and their researches formed the basis for many of the inventions and theories that are in use nowadays. Unfortunately, though their remarkable heritage materials, they are less well known. Therefore, the study will shed light on that forgotten heritage represented in devices, inventions and theories conceived by scientists and engineers of ancient Alexandria which, in some cases, can be considered precursors of contemporary sciences and technologies, demonstrating how the concept of science has been presented in the minds of ancient scientists and engineers since the 3rd century B.C. Findings revealed the remarkable impact of Alexandrian scholars' knowledge in terms of machine design and construction, thinking about the outside world, solving problems, and founding new curriculums. The chosen samples are presented and classified according to the significant of their inventors.