<p>In a side-by-side comparison, I’d like to see how truly different the custom version and the general textbook really are. In a discipline like Calculus, I tend to doubt that there’s a substantive difference, or at least a difference that results in a critical change in learning outcomes for the students. Think about it. Is it financially optimal for a publisher to simultaneously produce different editions at Berkeley, RPI and Alabama? Only if the investment is cheap and the return is significant. Also, I understand that ‘Stewart’s Calculus’ has been around for ages, so the publisher’s sunk costs were probably recovered long ago.</p>