Complex sentence: Leftist Thought in Twentieth-Century America is a book by American philosopher Richard Rorty, in which Rorty differentiates between what he sees as the two sides of the Left, a critical Left and a progressive Left.
Split into simpler sentences: Leftist Thought in Twentieth-Century America is a book by American philosopher Richard Rorty. In this book, Rorty differentiates between what he sees as the two sides of the Left, a critical Left and a progressive Left.