" Martin Heidegger’s challenge to Husserl came in the opening lines of a book, Sein und Zeit (Being and Time), which he published in Husserl’s own phenomenological Yearbook series in 1927. The first page contained an innocuous-seeming quotation from Plato’s dialogue The Sophist: For manifestly you have long been aware of what you mean when you use the expression ‘being’. We, however, who used to think we understood it, have now become perplexed. "

― Sarah Bakewell , At the Existentialist Café: Freedom, Being, and Apricot Cocktails