Workbooks are crap but you should read to your child.

If your child is as advanced as you say she is, then clearly whatever your wife does is working.

Why is no one reading to this child? Four years old is literally the perfect age for this! All this yapping about books and bookcases is totally missing the point: OP, just pick up 2 books a night and read to your kid. Problem of "extraneous" books solved.