In this short book, he recounts what he and others have learned about the sources of economic growth. This book conveys the way he tackled research problems. For Griliches, economic theorizing without measurement is merely the fashioning of parables, but measurement without theory is blind.
Judgment enables one to strike the right balance.
The book begins with economists' first attempts to measure productivity growth systematically in the 1930s. In the mid-1950s these efforts culminated in a startling puzzle. The growth of measured inputs like labor and capital explained only a fraction of the growth of national output. What explained the rest of economic growth quickly became one of the most important questions in economics. In 1973, after the oil price shocks, productivity growth slowed and the residual almost disappeared.