four buddha bodies - Thubten Chodron

These are the nature dharmakāya, wisdom dharmakāya, enjoyment body, and emanation body.

Nirvana in the Pali tradition
Continuing teaching from Chapter 11, covering non-abiding nirvana and nirvana as the cessation of duhkha and it's origins.
Glossary: buddha
Equality of samsara and nirvana
Completing teaching from Chapter 12, explaining various meanings of "equality of samsara and nirvana" and how clear light mind is understood according to sutra and tantra vehicles.
70 Topics: The four buddha bodies
Teaching on chapter 8 on the buddha bodies and a buddha's exalted activities.
Are sentient beings already Buddhas?
Explaining whether sentient beings are already buddhas and covering the buddha nature according to tantra, from the sections "Buddha Nature according to the Madhyamaka School" and “Buddha Nature according to Tantra", in Chapter 13.