Type description
ISTJs thrive on organization. They keep their lives and environments well-regulated. They bring painstaking attention to detail in their work and will not rest until a job is well completed.[12] They are often dissatisfied with unresolved issues, whether in life or in fiction.
ISTJs are faithful, logical, organized, sensible, and earnest traditionalists. They earn success by thoroughness and dependability. Shutting out distractions, they take a practical, logical approach to their endeavors. Realistic and responsible, they work steadily toward their goals. They enjoy creating order in both their professional and personal lives.
Despite their focus on their internal world, ISTJs prefer dealing with the present and the factual. Keen observers of life, they weigh various options when making decisions. ISTJs are well-prepared for most eventualities and have a good understanding of most situations. They believe in practical objectives, and they value traditions and loyalty.
For the Keirsey description, see Inspector (Role Variant).
[edit] Learning
ISTJs learn best and apply themselves to subjects that they deem practical and useful. As learners, ISTJs tend to need materials, directions, and teachers to be precise and accurate if they are to trust the information that is presented. They prefer concrete and useful applications and will tolerate theory only if it leads to these ends.
They like learning activities that allow them time to reflect and think. Material that seems too easy or too enjoyable leads ISTJs to be skeptical of its merit. Because of their practical outlook, ISTJs clearly delineate between work and play. Therefore, their ideal learning environment is task-oriented, has a clear schedule, and has a clear and precise assignment.
[edit] Working
ISTJs respect facts. They hold a tremendous store of data within themselves, gathered through their Sensing function. They may have difficulty valuing a theory or idea that differs from their own perspective. However, if they are shown the importance or relevance of the idea by someone whom they respect or care about, the idea becomes a fact that the ISTJ will internalize and vigorously support.
ISTJs often work for long periods, devoting their energy to tasks that they see as important to fulfilling a goal. However, they resist putting energy into things that don't make sense to them, or for which they can't see a practical application. They prefer to work alone but can work well in teams when the situation demands it. They like to be accountable for their actions, and they enjoy positions of responsibility. They have little use for theory or abstract thinking, unless the practical application is clear.
In general, ISTJs are capable, logical, reasonable, and effective individuals with a deeply driven desire to promote security and peaceful living. They can be highly effective at achieving their goals—whatever those may be.