Unlike narratives that either travel a history of dead ideas or sycophants trying an exegesis of one or more authors; Garrett provides a summary discussion of the themes of personal identity (not consciousness) and the language use of the words. The thought experiments expand on the "brain in a vat" concept and are presented and argued compellingly. Check the table of contents as this book deliberately limits its scope and clearly states those limits. A summary work in philosophy is rare, so this is well worth adding to your library. While clear, it is heavy going since it assumes some familiarity with concepts from the philsophy of mind and philosophy of language. It is not about personality or "being" if that is your interest; nor does it treat psychology or neuroscience.