This version of Ear Training: Two Note Complete comes with no CDs. You need the CDs to work with this ear training method. The CDs can be ordered separately either in physical form or as MP3 via itunes or other on-line sources. Search for: Ear Training: Two Note Complete to find the CDs or digital audio. If you would like to order the Ear Training method with the CDs included please see the Spiral bound editions of this book. Search for Ear Training Two Note Volume 1 etc....There are six volumes.Ear Training: Two Note Complete is the next level up from the "Ear Training: One Note" Series. It is recommended to master the One Note Series and "Key Note Recognition" before attempting this book. This method for developing relative pitch ear training and key modulation recognition has been used with great success There are six CDs that can be purchased separately for this book. Through practice, the student eventually gains the ability to recognize the key and the names of any two notes played simultaneously. Each of the six separately available CDs concentate on a different two note combination.