Femtosecond (fs) laser pulses are among the shortest stimuli in contemporary experimental physics. Controlling the magnetic state of media with ultrashort laser pulses is a rapidly growing research area which promises to revolutionize information processing by achieving the fastest possible and least dissipative magnetic recording [1,2]. The interaction of light with electrons, within the electric-dipole mechanism, conserves the electron spin. As a result, the mechanisms allowing femtosecond optical control of magnetism are among the most heavily debated fundamental questions in contemporary condensed matter research. In my lecture I will review recent progress in the field of femtosecond opto-magnetism. Several examples revealing the ways to boost the susceptibility of magnetic metals and dielectrics to ultrafast optical excitation will be discussed. For instance, the importance of interfaces [3] and domain walls [4] will be emphasized in the case of femtosecond opto-magnetism of Co/Pt multilayers. We will highlight the role of rare-earth ions in the case of effective optical control of magnetism in orthoferrites [5] and the role of doping in the case of photo-magnetic recording in iron garnets [6]. It will be also shown that non-collinear spin structures are more susceptible to femtosecond laser excitation that their collinear counterparts [7].