Aczel has carved out a niche as a popularizer of mathematical concepts and their discoverers (pop science fast food). Descartes certainly deserves the attention but he deserves better than this book which reads like a magazine article stretched to booklength. Oddly, the book falls short both on mathematics, philosophy and as a biography. There is not much math and philosophy in this text. Descartes' contributions are not developped and compared to his time nor to the present. The only persistent interest of Aczel is Descartes' relationship with the Rosicrucians, which Aczel brings up again and again - without committing himself to a verdict whether Descartes was or was not a member. And the secret (set as the payoff of reading this book) is rather trivial. Neglecting Descartes' contribution to highlight such a detail was not a good decision.

The book also fails as a biography. Aczel is very unfamiliar with the 17th century and misinterpretes common courtesy formulas as signs of affection or sees Descartes' secrecy as exceptional when it was the norm of the scientists at the time. Europe is also a strange beast to him. Many of his impressions seem to be taken from his sources without a test of reality.

At least, the book is short and has a good number of black and white illustrations. ( )

I read this book a few months ago, but, rather than compose some notes on the text as I usually do when I finish reading a book, it just sort of skipped my mind. This probably says something about how I regarded the book. It is a fairly concise biography of Descartes, with the "secret notebook" (a lost notebook, more accurately, it seems) as the unifying theme. Somewhat interesting to read about the alleged connections with the Rosicrucians, but Aczel downplays those connections.

If I had the book close at hand, it would probably jog my memory as to what the great "secret" was. I believe it had something to do with a lost Greek architectural theory of proportion. Ok, nothing earthshattering - the title is apparently calculated to cash in on the vogue for lost secrets, i.e., the "Da Vinci Code". Interesting enough for a layperson interested more in Descartes life than in his philosophical or mathematical accomplishments.

I had read Amir Aczel's book on Fermat's Last Theorem, and I felt the same way, more confused than enlightened. The problem is that Mr. Aczel has a less than interesting style: the reading goes by very quickly and it just does not feel like one is gaining a lot of facts when one is gaining some facts. I thought Simon Singh did a better job with Fermat and I can't help but think that someone else can do a better job with this material.

It seems like Mr. Aczel has better things to do and more things to say at the end of the book, so he rushes to get to the good stuff only to reveal that there is very little good stuff.

Rene Descarte has always been a very interesting person to me. I had read a rather extensive biography of the man many years ago as an undergrad, so what Mr. Aczel had to bring to the story is interesting but not surprising. He does a pedantic job of relating the basics with some interesting tidbits thrown in, yet his style makes the interesting seem superficial.

The entire time, Mr. Aczel is moving towards the big mysterious reveal, the reason for yet another Descarte biography. He keeps hinting at a great earthshattering surprise, yet when it does come, the surprise is hardly surprising. The ingenious work that Descarte did in defiance of the church authorities of his day is indeed impressive but Mr. Aczel does not do the revelation justice. He never fully engages the reader in the development of the discovery and he fails to explain the difficulty of the mathematic is ignored altogether.

It is a good short treatment of Descarte's life, but there is no heft, very little mathematical detail, and nonexistent mystery in what is promised as a mysterious and revelatory book. ( )

As Aczel so deftly demonstrates, Descartes's mathematical theories were paths to an understanding the order and mystery of the cosmos, and he kept the notebook hidden because it contained a formula that—because it supported Copernicus's model of the solar system—Descartes feared would lead to his persecution by the Inquisition. Aczel lucidly explains the science, mystery and mathematics of Descartes, who has never been so lively as he is in the pages of this first-rate biography and social history.