This one is very borderline and I certainly won't be offended/surprised if it gets closed.

The London Maths Society (LMS) are thinking of (indeed, actively pursuing the idea of) reprinting "Algebraic number theory" Ed. Cassels and Froehlich. Hence the LMS had to go about contacting the authors of the original articles. When they contacted Serre he replied "sure reprint my articles, but please include the erratum that I indicated in my completed works." Sure enough, he had found a slip in one of his articles (in the statement of the "ugly lemma"---Serre went on to say that this had taught him not to abuse lemmas, as they might bite back!) and had taken the trouble to fix it when his completed works were published.

I looked over the thread from last October about the errata database but the database doesn't seem to contain this book. On the other hand it is surely a very widely-read book. I think I just found a typo in the definition of a co-induced module on p98: I think the $G$-action on $Hom_{G'}(\mathbf{Z}[G],A')$ ($G'$ a subgroup of $G$ and $A'$ a $G'$-module) should be that $g\in G$ sends $\phi$ to the function sending $g'$ to $\phi(g'g)$, not what the authors say (what they say isn't even an action as far as I can see, unless I made a slip). The notation is also terrible: $g'$ is in $G$, it seems to me.

Does anyone else have any scrawled marginal notes in their copies of Cassels-Froehlich about typos or other things that the LMS can fix? They are planning on having an erratum page at the beginning of the book when they reprint it.

If this thread does get closed, feel free to email comments to buzzard at imperial.ac.uk.