This fascinating book examines and offers critical comments on the new 'significant market power'-regime, as put into place by the 2003 European regulatory framework on electronic communications networks and services. An overview of this regime, its characteristics, guiding principles, and procedures is provided, using the mobile sector as a case study. The authors give a clear and comprehensive presentation of the new SMP-procedure that may lead to the imposition of remedies on undertakings with significant market power. The book also contains an analysis of all available European Commission comments on the notifications of draft measures by national regulatory authorities, for mobile as well as other markets. Addressing pressing issues, in view of the implementation of the new regulatory framework, this book is a useful working instrument for everyone who is active in the electronic communications sector including practicing lawyers, firms in the electronic communications sector, regulatory authorities, academics and policymakers throughout Europe.