That'd be Fred Brooks. The exact quote is

"Show me your code and conceal your data structures, and I shall continue to be mystified. Show me your data structures, and I won't usually need your code; it'll be obvious."

Kinda hard to believe now, but back in the days when we had to shovel coal to power our mammoth steam-belching, card fed computers, procedural code was the order of the day. The idea of organizing code around "data structures" was a strange one.