To outsiders, INTJs may appear to project an aura of "definiteness", of self-confidence. This self-confidence is rooted in the specialized knowledge systems that most INTJs start building up at an early age;  they know what they know -- and, just as importantly, what they don't know.

  Obvious INTJ careers are in science and engineering;  they rise to management level positions in these fields if they can use their pragmatism to regard the existing management and bureaucracy as tools rather than obstacles to be circumvented.  INTJs can also be found wherever a combination of intellect and incisiveness are required (law, some areas of academia, etc.).

  Personal relationships, particularly romantic ones, can be the INTJ's Achilles heel. While they are capable of caring deeply for others (usually a select few), and are willing to spend a great deal of time and effort on a relationship, the knowledge and self-confidence that make them so successful in other areas can suddenly abandon or mislead them in interpersonal situations.

  This happens in part because many INTJs do not readily grasp the social rituals; for instance, they tend to have little patience and less understanding of such things as small talk and flirtation (which most types consider half the fun of a relationship). To complicate matters, INTJs are usually extremely private people, and can often be naturally impassive as well, which makes them easy to misread and misunderstand. Perhaps the most fundamental problem, however, is that INTJs really want people to make *sense*. :-) This sometimes results in a peculiar naiveté', paralleling that of many Fs -- only instead of expecting inexhaustible affection and empathy from a romantic relationship, the INTJ will expect inexhaustible reasonability and directness.

          Famous INTJs:

          Augustus Caesar (Gaius Julius Caesar Octavianus), Emperor of Rome
          Hannibal, Carthaginian military leader
          Ivan Lendl, tennis champion
          Martina Navratilova, tennis champion
          U.S. Presidents:
                   Thomas Jefferson
                   John F. Kennedy

          Fictional:
 
          Hannibal Lecter (Silence of the Lambs)
          Professor Moritarty, Sherlock Holmes's nemesis
          Ensign Ro (Star Trek - the Next Generation)