What major issue did Rudolph Flesch's book bring to public attention in 1955?

Rudolph Flesch's book "Why Johnny Can't Read," published in 1955, significantly impacted public discourse regarding reading education by highlighting the critical relationship between phonics and reading instruction. The book's central argument was that the reliance on sight words and whole language approaches in schools was contributing to widespread reading difficulties among children. Flesch stressed that a solid foundation in phonics—understanding the relationships between letters and sounds—is essential for effective reading. By bringing this issue to light, the book spurred debates and discussions that shifted focus back to phonics-based instruction in reading programs, thus influencing educational practices for years to come. This emphasis on the importance of phonics, which is foundational in helping children decode words and develop reading fluency, remains a significant topic in literacy education today.