The purpose of this book, is to study some subclasses of analytic univalent, multivalent and bi - univalent functions defined by using some linear operators in the open unit disk U={z C: z <1}. Some of these subclasses are generalizations of other classes which are previously studied. Some properties of p - valent functions and spiral - like functions associated with various integral operators are studying by using integral operator called (R - K) integral operator. Some geometric properties are obtained and such us coefficient estimates and study the (H - R) fractional calculus of the class. Some applications of Multiplier transformation was presented such as, integral operator and Bernoulli polynomial to obtain geometric properties of the class. We have also discussed some properties of a subclass of harmonic univalent and multivalent functions with integral operators. Also coefficients estimates for certain a class of bi - univalent functions involving generalized operator anda new class of bi - univalent functions defined by Salagen operator with some applications of Hermite and Lagurr polynomials is discussing.