The peculiar and important characteristic of this book is to present numerical simulations and models of both stellar and extragalactic jets, together with review papers outlining the state-of-the-art of the observations of jets. In fact, other books on jets deal either with stellar jets or extragalactic jets separately but are lacking, until now, a more global view. The authors of these contributions are among the most active scientists in the field of theoretical interpretation of the astrophysical jets phenomenology. The book is intended for readers that are carrying out research in the fields of accretion and outflow phenomena in astrophysics, star formation, Active Galactic Nuclei, computational fluid dynamics and magneto-hydrodynamics applied to astrophysics.