About this site


In 1996 I was the Ulam Visiting Professor at the University of Colorado, Boulder. While I was there I gave a series of graduate lectures on high-dimensional manifold theory, which I whimsically titled Surgery for Amateurs.

The title was supposed to express that I was coming to the subject from outside.   In fact, I was trying to answer to my own satisfaction the question “What is this Novikov Conjecture you keep talking about?” – it was aggravating to keep explaining that my work was significant because of its relation to this other thing that I didn’t understand properly. Perhaps because of their amateurish nature, though, these lectures struck a chord, and I have received many requests for reprints of the lecture notes. In 2004 I began a project of revising them with the help of Andrew Ranicki; but, alas, other parts of life intervened, and the proposed book never got finished.  With both Andrew and I now suffering from cancer, it never will.

A while ago I created this website in an attempt to blog my way through the (non-existent) book, hoping that in this way I might bully myself into writing it. That didn’t work either, though it did generate some blog posts containing interesting side discussions, at least to me.

I’m now putting the site to sleep, as it were, and providing various versions of the “story so far” in case they are helpful to anyone. We did keep starting over and that means that there are several versions of Surgery for Amateurs in circulation.  Rather than try to combine them (a project for which I have no energy) I am simply presenting them side by side.  Thus the book versions page on this site contains

  • The “2004 text”, largely the notes as I had originally written them, which are probably somewhat more geometrical in tone, go a way further with the material, but tell a few lies in the process.
  • The “2013 text”, which begins the process of explaining the details using Andrew Ranicki’s quadratic algebra, but does not reach the main theorems and applications.
  • The “2017 text”, which covers much the same material as the 2013 text but has been further revised by Andrew.
  • Blog posts from my attempt to blog my way through the book, most closely correlated with the 2013 text.  You are in fact looking at the blog now – the posts continue below this announcement, which is pinned to the front page.

As I said, I hope that you find some of this material useful.  If you are moved to cite it, please refer to “Surgery for Amateurs” (https://sites.psu.edu/surgeryforamateurs) by Andrew Ranicki and John Roe.

Thanks very much!



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