There is a wide spectrum for discovering new drugs and new uses for marketed drugs that ranges from purely rational to that of pure chance or serendipity.

There are three key levels to think about various issues and topics: the overall industry, the specific company and a specific drug or product.

In the past, time was generally viewed in drug development (particularly in large companies) as the single most precious resource you had to spend, but in recent years the importance of financial resources has become steadily more important, and often has become the most critical factor.