Chapter one of Igeres Hateshuva introduces the Mitzva of Teshuva at its most basic; reflecting the possibility for anyone who so desires to do Teshuva successfully.

Chapters 1-3 also address the question of fasts as they do or don’t relate to Teshuva.

Chapter 4 begins the mystical interpretation of Teshuva. What we do has an affect on high also. Two Teshuvos, The lower and higher Heis of Hashem’s name.

Chapters 4-6 discuss Yiddishkeit in the time of the Beis Hamikdash vs. the times of Golus. These two disparate worlds can be described as normal vs. extreme. Golus has several advantages. One of them appears to be Teshuva (in the mystical sense at least).

Chapter six in Iggeres hateshuva discusses Golus. During that time the lines between kedusha and Kelipa can get crossed (as kedusha itself is in exile). The result is A Yid can live from and give life to kelipa. This also explains the mystical concept of Teshuva (Returning to Kedusha what is rightfully his).

Chapters 7-8 discuss Teshuva Tataa (lower Teshuva) with the mystical perspective. Three steps of Teshuva are 1. Feel compassion for damage done 2. the brokenheartedness of failure 3. evoking divine mercies to heal.

Chapters 8-9 discuss Teshuva Ilaa (higher Teshuva) on the mystical perspective. No wrong can affect the higher HEY directly but sins on the lower level (HEY) preclude access to this higher level. After one does the lower Teshuva the possibility for access to the inner dimension of Yiddishkeit emerges. This higher Teshuva is all positive-...

Chapter 10. Teshuva has two levels but one must go in order- Lower Teshuva leads to higher teshuva.

Chapters 11-12. The joy of Teshuva. This doesn’t contradict one’s need to be forever vigilant about those things one has been weak about in the past. The Rebbe’s unique idea about positiveness in teshuva in our times.