Rhythm Reader, designed to build rhythm readiness skills in singers, is a necessary resource for all choirs. Originally designed as a supplemental teaching resource for the SOS: Simply our Sight-reading book (BLB9), singers of all abilities will benefit from the review and drill afforded in this teaching and learning resource. May be used with or independently from BLB9 SOS: Simplify our Sight Reading, BLB10 Treble Supplemental Flashcards & BLB11 Bass Supplemental Flashcards.