The very first schoolbook that was written had God all over it.
The teaching power of a schoolbook cannot be weighed in the grocer's scales nor measured with a pint cup.
But you told this to Marina because of the association of Lee Oswald with the schoolbook depository?
But the final real judge of the merits of a schoolbook is the boy or girl who uses it.
John Milton was "the most notable man who ever kept school or published a schoolbook."
It is designed for a schoolbook, and evinces both learning and fairness.