ABSTRACT
One of the first laws of nature is that no two things are identical. No two chromatographic columns are exactly alike. No two batches produced in a chemical or biological process are quite the same. Every day people in the pharmaceutical industry struggle to understand and explain variation and deviations. This struggle can be traced from the origins of manufacturing to the present. An enormous amount of time, money, and energy continues to be invested in this effort. In order to understand from where our current practices spring, as well as the superior approaches that have evolved in recent times, it is instructive to take a historical perspective.
