In chapter 11 we state that "The real yield curve is a plot of real gross redemption yields on index-linked bonds against term to maturity." Why only index-linked bonds? As long as we are considering real gross yield, why not take fixed interest bonds into account as well?
You are correct that in theory you could calculate this yield curve for a fixed-interest bond but investors purchasing fixed-interest bonds are most likely to have nominal liabilities they are seeking to match and therefore interested in the nominal (rather than real) return.