This introduction to algebraic geometry makes particular reference to the operation of inversion and is suitable for advanced undergraduates and graduate students of mathematics. One of the major contributions to the relatively small literature on inversive geometry, the text illustrates the field's applications to comparatively elementary and practical questions and offers a solid foundation for more advanced courses.The two-part treatment begins with the applications of numbers to Euclid's planar geometry, covering inversions; quadratics; the inversive group of the plane; finite inversive groups; parabolic, hyperbolic, and elliptic geometries; the celestial sphere; flow; and differential geometry. The second part addresses the line and the circle; regular polygons; motions; the triangle; invariants under homologies; rational curves; conics; the cardioid and the deltoid; Cremona transformations; and the n-line.