Upasamānussati: 'recollection of the peace of Nibbana', is the last of the 10 recollections anussati. Whatsoever, o Bhikkhus, there are of things, as highest of them is considered detachment viraga i.e. the crushing of conceit, the stilling of thirst, the uprooting of clinging, the breaking through the round of rebirths, cessation of craving, detachment, ceasing, Nibbana; A. IV, 34.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.