Euclid
Byrne's Edition of Euclid, Euclid and the Elements, Euclid Elements - the Perseus Project, Euclid Forum Frigate, Euclid in Verse, Euclid of Alexandria, Euclid's Elements, Euclid's Elements - Joyce's Java version, Introduction to the Works of Euclid, Introduction to the Works of Euclid
Apollonius of Perga (c. 262-190 B.C.)
known as 'The Great Geometer', great influence on the development of mathematics, famous book Conics introduced terms such as parabola, ellipse and hyperbola.
Desargues - Girard Desargues (1591-1661)
Founder of projective geometry, his work centred on the theory of conic sections and perspective.
Heron of Alexandria (ca. 75 AD)
Greek mathematician who was mainly interested in practical studies in mechanics and engineering, best known for Heron's Formula
Klein, Felix (1849-1925)
Plücker's assistant at Bonn who studied Analytic Geometry, describing geometry as the study of properties of figures which remain invariant under a Group of Transformations. He systemized Non-Euclidean Geometry.
Monge, Gaspard - Conte de Péluse (1746-1818)
The father of differential geometry, he devised a system called Geometrie descriptive, now known as orthographic projection, the graphical method used in modern mechanical drawing.
Pappus of Alexandria (c. 320)
Wrote treatise, the Mathematical Collection, as a guide to Greek geometry, discusses theorems and constructions of more than thirty different mathematicians of antiquity.
Riemann, Georg Friedrich Bernhard (1826-1866)
Theory of functions, non-Euclidian geometry, relativity theory, Famous for the Riemann hypothesis about the behavior of zeros of the Riemann zeta function, which he showed determines the distribution of prime numbers.
Steiner, Jakob (1796-1863)
Was one of the greatest contributors to projective geometry.