deceptively casual = contains deeper / hidden meaning Preface - the text in a book, usually on the first page, that raises awareness to the content

It would be clearer to include more punctuation: "That’s Oliver Sacks' reading, a deceptively casual preface to his most recent book." or "That’s Oliver Sacks' reading: a deceptively casual preface to his most recent book." "Oliver Sacks' " <-- when the word ends in an 's,' the posessive form (the book belongs to Oliver Sacks) has an apostrophe after the 's'. If his name were just 'Sack, ' it would be Oliver Sack's reading. "That's Oliver Sacks' reading, "<-- the comma separates two phrases, one independent (it can be a sentence on its own), the other dependent (it requires and it modifies the independent one). Here, the independent one is first "That's Oliver Sacks' reading_" could have a comma or a period in the space. OR "That's Oliver Sacks' reading: "<-- the colon indicates that we are going to define something. As in, "this is what Oliver Sacks' reading is, I am defining it right here: " ", a deceptively casual preface to his new book." <-- this is the dependent phrase, after the comma. It can't be a sentence by itself because it does not have a verb. "deceptively" <-- tricky, deceiving, not what it first appears to be "deceptively casual" <-- It looks casual or simple or easy, but it is really not that. It is more complex or has deeper meaning than it appears. "preface to his most recent book" <-- the introductory part of a book, before the chapters start. The full, more complicated meaning of the sentence requires you to infer two big things: (1) what is happening with "Oliver Sacks' reading" and (2) who 'his' is referring to. (1) Oliver Sacks read this preface to a book. He now has a 'reading.' He has then discussed or written about his reading with someone else, now we are going to describe Oliver Sacks' reading. (2) Without surrounding sentences, we can't be certain, but 'his' probably means another person's. In summary: Oliver read somebody's book. Oliver thinks the preface section makes the book look simple, but the book is not simple.

Presumably you just heard Oliver Sacks reading (on the radio?) from the preface to his latest book, the text of which has a casual tone that doesn't reflect its underlying seriousness or intensity. You could be deceived by its apparent casualness. I have read a lot of Oliver Sacks and found nothing casual about his writing. He is passionate and overflowing with ideas, a good many of which he puts in the footnotes.