This tricentennial tribute commemorates Euler's major contributions to mathematical and physical sciences. A brief biographical sketch is presented with his major contributions to certain selected areas of number theory, differential and integral calculus, differential equations, solid and fluid mechanics, topology and graph theory, infinite products, infinite series, elliptic integrals, calculus of variations and the Fourier coefficients. This short article is written to provide a definite impression of Euler's personal and professional life as well as of the range, power and depth of his unique contributions to mathematical and physical sciences. By any standards, his legacy of complete works entitled "Opera Omnia" of nearly 80 volumes will remain forever as a remarkable example of his scholarly work in the history of mathematics and sciences. (Contains 4 figures.)