This volume contains five tutorial papers based on the lectures given at the intensive course on Software Reliability Modelling and Identification in Como (Italy) from September 2 to 4, 1987. The purpose of this volume is to present some important models used to forecast the reliability growth during the software testing process, and discuss the practical applicability of models in the management of software techniques for model identification from data (parameter estimation, complexity selection, validation, etc.). The basic reliability concepts are also introduced for those readers who are not familiar with the reliability ideas. Besides the basic models, a new family of models is introduced in the book. This family is flexible enough to describe a variety of different reliability trends. Particular attention is given to the problem of the provision of tools to assist the user in selecting an appropriate model in a particular situation.