What is the author's style in Letters from a Stoic Epistulae Morales Ad Lucilium by Seneca?

This collection is composed of forty-two letters taken from the 124 letters of the "Epistulae Morales ad Lucilium." For the most part, the collection's editor included only letters he judged to be of interest to a student wishing to understand Seneca's flavor of Stoic philosopher. Accordingly, many of the letters which are included have been pruned of passages which are either superfluous or repeat themes that have been thoroughly discussed elsewhere.