Mr. Silverman has done a good job putting together the results of the many studies that show how our English spelling can hurt children learning to read and write. To be sure, not all children have much trouble with our system, such as it is; I myself have always been a good speller, not that I can take any credit for it; it's just one of those things we can be born with, like being tall or having big feet. But the unpredictability of English spelling can take a toll on many children. Studies have shown that dyslexia and other reading disorders are mostly unknown among, say, Finnish speaking children, Finnish often being held up as the model for a nearly flawless phonemic spelling system; while English speaking and French speaking children in particular are far more likely to have dyslexia--and English and French are notorious for having badly outdated and unphonemic spelling.
Where Mr. Silverman's book falls short of what it could have been is in the system he puts forth as a new way to spell English, at least as far as I see it. He urges English speakers to adopt a phonemic system, and on that I agree with him. But his specific system is, I think, badly thought through. One big drawback to English spelling, one Silverman rightly calls out, is that there are more phonemes in English than there are letters. Silverman tries to do something about this, but where he goes wrong is that rather than stealing--or borrowing, if you like--letters from other languages, he chooses to stock his broadened alphabet with such random signs as ^ and /. Languages that use the Latin alphabet abound with such useful characters as å, ø, ð, ñ, þ and ç, among many others. There's no need to stock up on random doodads that have no capitals like ^ when you could use a handy æ instead.