I am an observational astrophysicist working in the field of supernovae. I first got interested in this subject through the use of Type Ia supernovae as powerful distance indicators in the study of the expansion history of the Universe. I focused on the use of spectroscopy and multi-band photometry as a means to improve the precision of distance measurements. In the past few years, I also became interested in understanding supernovae as astrophysical objects in connection with stellar evolution, the mechanism of explosion, and the interaction with the interstellar medium. For that purpose I have been involved in the monitoring of all types of supernovae very soon after explosion.