COSTP was a not-for-profit, collaborative, public/private undertaking originally created to address the high cost, content range, and consistent shortages of K-12 textbooks in California.
COSTP's mandate later expanded to include undergraduate and graduate university instructional materials, covering the entire K-20 range.
Critics contended that publishing companies artificially increased prices and essentially shut out competing efforts to liberate academic content from traditional copyright control.
COSTP made important contributions to the many organizations that followed in its wake, as the "Open Educational Content" movement took hold over the next 10–15 years.
It is important to note that COSTP's mandate was not to replace printed textbooks, but simply make them less expensive to produce and distribute, thus creating many additional efficiencies in the K-12 academic content sector.