Readings from The Island by Ajahn Pasanno and Ajahn Amaro, Chapter 5, pp. 87-92. Read by Ajahn Amaro:
“Nibbāna,” Buddhist Dictionary: A Manual of Buddhist Terms and Doctrines by Venerable Ñāṇatiloka, p. 124.
Suttas: MN 140.31; Dhp 21; AN 6.49; SN 22.49; SN 1.20; Nid 80.226; MN 144.9; SN 22.59 (also at Mahāvagga 1.6).