What are mental concepts? Why do they work the way they do? How can they be captured in language? How can they be captured in a computer? The authors describe the development of, and clearly explain, the underlying linguistic theory and the working software they have developed over 40 years to store declarative knowledge in a computer fully to the same level as language, knowledge accessible via ordinary conversation. During this 40 year project there was no epiphany, no "Eureka moment," except perhaps for the day that their parser program successfully parsed a long sentence for the first...