This year I gave my lecture at the Newton Institute in Cambridge as part of a six-month program on noncommutative geometry. Most of my mathematical activity has consisted in completing the book written with Matilde Marcolli and entitled : " Noncommutative geometry, quantum fields and motives ", which will be published by the AMS and Hindustan book agency.
In this Abstract, I will present some variations on the central notion of the spectral triplet, which serves as a paradigm in noncommutative geometry.