1) This letter welcomes 4th grade students and families to a new school year and introduces Mr. O'Brien as their teacher. It highlights that this is the last year at their current school and the year they will attend Wolf Ridge. 2) It provides information about class blogs to stay updated on class happenings and homework assignments. It also lists important first day details like class being divided into specials groups and recess/lunch time. 3) The teacher shares that he had a busy summer teaching, playing sports, and coaching but is looking forward to meeting the students and having an excellent school year.