Type I supernovae as distance indicators

Type I supernovae can be used to determine the distance in three ways: (a) As standard candles. (b) Through the Baade-Wesselink method. (c) Through dynamical methods. The first on relies on the remarkable spectrophotometric homogeneity of type I supernovae. The second one on the expansion of a well-defined photosphere. The third one on the existence of specific theoretical models for SNI explosions. We critically examine these methods and we point out the items that deserve closer examination.