Neil Kjos-This well organized method can be used with church or school groups private students or voice classes. Book1 is written for grade four while Book 2 reviews skills progressing into more difficult sight-singing for advanced high school to University level.This creative step by step approach gives singers the skills needed to sight-sing by themselves away from a piano or other singers. Book 1 is designed for unison or two-part singing while Book 2 contains two-part or three-part. This method introduces rhythms and intervals sequentially and systematically incorporates elements of music such as key signatures and changing time signatures with regular reviews.TheTeachers Edition contains all material found in the Vocal Edition plus detailed instructions for each lesson.