Known as the "Inspectors",they are SUPER dependable and responsible. They usually always follow rules and try to get others to also. If there is a paper due, an ISTJ will have it done 2 weeks before and have it in at the exact time it's due,or earlier. They usually want everyone to follow the rules like they do. So if you ever get snitched on for something it was most likely an ISTJ that told. They have a big respect for authority and won't question it. They tend to be shy and quiet.