It is just about conceivable that writers can continue to amaze at an advanced age, even up until they die. It's much more common for one of two things to happen: after a certain point, either they disappoint – because there is an obvious falling off or because we realise we are getting fed more and more of the same – or they are taken for granted.
Occasionally, both can happen, in which case (Philip Roth's, for example) we take our disappointment for granted and just wait for him or her to shut up. Milan Kundera is an extreme case in that we take our amazement for granted. Think back to whenever it was that you first read The Book of Laughter and Forgetting or The Unbearable Lightness of Being and remember how exciting these "novels in the form of variations" seemed in terms of conception, content and orchestration. It wasn't just a question of technical novelty: the idea of fiction was recalibrated to create forms of new knowledge.
We may subsequently have become a little weary of the conventionally novelistic sections of these books – one remembers them in terms of randy doctors Benny Hillishly chasing nurses in their panties – but with Testaments Betrayed Kundera dispensed with characters, stories and situations while retaining his signature technique of "meditative interrogation" to construct a book entirely of novelistic essays. To say he became an influence (in the way that Martin Amis is influential) is to understate matters. Kundera's distinctive, pioneering software became available for download and has been used by, among others, Adam Thirlwell (precociously) in Politics and Craig Raine (bit lame at his age) in Heartbreak.
The man himself, meanwhile, had switched from Czech to French (pretty amazing in itself), producing three shortish novels and another stimulating essay in the form of variations, The Curtain. The opposite of a curtain-raiser, Encounter is a curtain lowerer or encore: a linked collection of pieces originally written in French, some from 20 years ago, modestly offering themselves as "reflections and recollections" on "old themes (existential and aesthetic) and… old loves".
It is a tribute to Kundera's ability to weave his essayistic spell that my interest was undiminished by the fact that I am either wholly ignorant of many of the composers and writers discussed (Iannis Xenakis, Marek Bienczyk, Gudbergur Bergsson) correct or am familiar with them only through Kundera's earlier books. In any case, Kundera's subjects are mirrors, offering variously distorted reflections on his own work and situation. As he says with reference to a remark by Francis Bacon about Beckett: "When one artist is talking about another, he is always talking (indirectly, in a roundabout way) of himself, and that is what's valuable in his judgment."