From the author:

WORKING WITH SOUNDS is designed to assist pupils in putting sounds to work in attacking words. Putting sounds and syllables
to work is essential if pupils are to become independent readers. People cannot be expected to understand and react to the ideas of a writer if they cannot identify the printed words which convey the ideas. To help develop these word identification skills is the job of WORKING WITH SOUNDS. Some of the units are designed to develop understandings about sound-symbol associations.
Other units are geared to give the reader many opportunities for immediate application of newly developed understanding and skill in realistic, functional settings. On the upper levels many units feature concept development and application.

Note; The material presented reflects learner expectations for Grade 3 in 1976.