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Spectrum usually has excellent workbooks that are on, or even slightly above, grade-level. This book is the only disappointment I have encountered from their series. It is essentially a phonemic awareness book, covering the letters and their sounds, with a little bit of beginning and ending sound work. But that's it. No c-v-c words, no blending, not even word families like "at" and "un." So while it's a perfectly fine book for what it is, it is definitely not a thorough kindergarten-level phonics book. I'd say it's more appropriate for preschool (age 4) or for kindergarteners who still need to work on mastering their letter sounds. If your kindergartener is solid on the letters sounds and is beginning to blend simple words like "cat," you would do best to pass on this and either get the 1st grade Spectrum book or go for a different program altogether, like Pearson Phonics Level A or Explode the Code 1, both of which I highly recommend.