This book, ?Nonlinear Interactions of femtosecond pulses with transparent media,? is an attempt to disseminate few important results obtained recently that enables the readers to understand the rich physics involved in the light-matter interactions in femtosecond (fs) regime. With the high intensities available from fs laser pulses, the subject becomes much richer, as the pulse itself affects and is affected by the material it propagates through, in dramatic ways. Interactions representing both these classes form the subject of this book. Considering the vast nature of this subject we limit ourselves in this book to the second and third order nonlinear phenomena namely, supercontinuum generation, mulitphoton absorption and surface enahanced third order processes demonstrated with four-wave mixing at surfaces.