ISTPs are factual, sensible, logical and reflective. They enjoy activity, independence and solitude and may work happily and productively for 20 hours at a stretch. Curious, practical and often mechanically adept, many excellent craftsmen and production artists are ISTPs, as are professionals in electronics, engineering and mechanics and stars in individual athletic competition and team sports. ISTPs are masterful at analyzing complex systems and introducing change to improve productivity and efficiency. This type is noted for working out easier ways to get things done: often a great asset, but also a potential liability if the ISTP side-steps regulations, codes and laws. In business and finance, ISTPs often rise to the top because they combine a no-nonsense facts-and-figures approach with a "why not try it?" openness to strategy. They tend to be objective, competitive and coolly rational in most life pursuits. More feeling types may perceive the ISTP's approach to personal relationships as detached, conditional and utilitarian, but ISTPs retort that their behavior is merely unemotional.

ISTPs have a compelling drive to understand the way things work. They're good at logical analysis, and like to use it on practical concerns. They typically have strong powers of reasoning, although they're not interested in theories or concepts unless they can see a practical application. They like to take things apart and see the way they work.

ISTPs have an adventuresome spirit. They are attracted to motorcycles, airplanes, sky diving, surfing, etc. They thrive on action, and are usually fearless. ISTPs are fiercely independent, needing to have the space to make their own decisions about their next step. They do not believe in or follow rules and regulations, as this would prohibit their ability to "do their own thing". Their sense of adventure and desire for constant action makes ISTPs prone to becoming bored rather quickly.

ISTPs are loyal to their causes and beliefs, and are firm believers that people should be treated with equity and fairness. Although they do not respect the rules of the "System", they follow their own rules and guidelines for behavior faithfully. They will not take part in something which violates their personal laws. ISTPs are extremely loyal and faithful to their "brothers".

ISTPs like and need to spend time alone, because this is when they can sort things out in their minds most clearly. They absorb large quantities of impersonal facts from the external world, and sort through those facts, making judgments, when they are alone.

ISTPs are action-oriented people. They like to be up and about, doing things. They are not people to sit behind a desk all day and do long-range planning. Adaptable and spontaneous, they respond to what is immediately before them. They usually have strong technical skills, and can be effective technical leaders. They focus on details and practical things. They have an excellent sense of expediency and grasp of the details which enables them to make quick, effective decisions.

ISTPs avoid making judgments based on personal values - they feel that judgments and decisions should be made impartially, based on the fact. They are not naturally tuned in to how they are affecting others. They do not pay attention to their own feelings, and even distrust them and try to ignore them, because they have difficulty distinguishing between emotional reactions and value judgments. This may be a problem area for many ISTPs.

An ISTP who is over-stressed may exhibit rash emotional outbursts of anger, or on the other extreme may be overwhelmed by emotions and feelings which they feel compelled to share with people (often inappropriately). An ISTP who is down on themself will foray into the world of value judgments - a place which is not natural for the ISTP - and judge themself by their inability to perform some task. They will then approach the task in a grim emotional state, expecting the worst.

ISTPs are excellent in a crisis situations. They're usually good athletes, and have very good hand-eye coordination. They are good at following through with a project, and tying up loose ends. They usually don't have much trouble with school, because they are introverts who can think logically. They are usually patient individuals, although they may be prone to occasional emotional outbursts due to their inattention to their own feelings.

ISTPs have a lot of natural ability which makes them good at many different kinds of things. However, they are happiest when they are centered in action-oriented tasks which require detailed logical analysis and technical skill. They take pride in their ability to take the next correct step.

ISTPs are optimistic, full of good cheer, loyal to their equals, uncomplicated in their desires, generous, trusting and receptive people who want no part in confining commitments.

Like their fellow SPs, ISTPs are fundamentally Performers (note the capital 'P' :-)), but as Ts their areas of interest tend to be mechanical rather than artistic like those of ISFPs, and unlike most ESPs they do not present an impression of constant activity. On the contrary, they lie dormant, saving their energy until a project or an adventure worthy of their time comes along--and then they launch themselves at it. The apparently frenzied state that inevitably ensues is actually much more controlled than it appears--ISTPs always seem to know what they're doing when it comes to physical or mechanical obstacles--but the whole chain of events presents a confusing and paradoxical picture to an outsider.

ISTPs are equally difficult to understand in their need for personal space, which in turn has an impact on their relationships with others. They need to be able to "spread out"--both physically and psychologically--which generally implies encroaching to some degree on others, especially if they decide that something of someone else's is going to become their next project. (They are generally quite comfortable, however, with being treated the same way they treat others--at least in this respect.) But because they need such a lot of flexibility to be as spontaneous as they feel they must be, they tend to become as inflexible as the most rigid J when someone seems to be threatening their lifestyle (although they usually respond with a classic SP rage which is yet another vivid contrast to their "dormant," impassive, detached mode). These territorial considerations are usually critical in relationships with ISTPs; communication also tends to be a key issue, since they generally express themselves non-verbally. When they do actually verbalize, ISTPs are masters of the one-liner, often showing flashes of humor in the most tense situations; this can result in their being seen as thick-skinned or tasteless.

Like most SPs, ISTPs may have trouble with rote and abstract classroom learning, which tend not to be good measures of their actual intelligence. They tend, sometimes with good reason, to be highly skeptical of its practical value, and often gravitate towards classes in industrial arts; part-time vocational/ technical programs can be useful to even the college-bound ISTP. In terms of careers, mechanics and any of the skilled trades are traditional choices, and those ISTPs with strong numerical as well mechanical gifts tend to do extremely well in most areas of engineering. Working as paramedics or firefighters can fulfill the ISTP need to live on the edge; they are at their best in a crisis, where their natural disregard for rules and authority structures allows them to focus on and tackle the emergency at hand in the most effective way.

ISTPs with more sedate careers usually take on high-risk avocations like racing, skydiving, and motorcycling. While aware of the dangers involved, they are so in touch with the physical world that they know they can get away with much smaller safety margins than other types.