Dr. David Mark Keirsey is a scientist that is interested in how and why the world works.

The first half of his professional career was as a Computer Scientist, specializing in Artificial Intelligence. Notably, he was part of a team who created the software for the first operation of an autonomous cross-country robotic vehicle. In the current latter part of his career, he has broaden his interest to include all of science, mathematics, computation, and the history and future of the world.

His plan is to write at least three books, two of which are tentatively called Mathematics Itself and Existence Itself. The third is a book on Leadership. Currently he is part of a web-based company, Advisorteam.com to develop interactive team and human personality tools based on his father's best-selling work on human temperament.

He is a Architect Rational in temperament.