Like many fans of IM Jeremy Silman's works, I impatiently await the release of his 4th edition of "How to Reassess Your Chess", so I wrote to him and share with you his answer:

"A lot of people are asking me about this, so here’s my “stump” reply:

The 4th edition, which is a TOTAL rewrite (every example thrown out and
everything in it 100% new ... Including
new chapters and ideas) has proved to be extremely complex to write. As you
know, I won’t let a book go to press
unless I feel it offers something new and important. So I’m taking this book
very seriously and won’t rush it. I’m
actually spending up to 12 hours a day on this thing, and have done a lot.
However, I’m still a long way from finishing.
I now hope (best case scenario) to have it out by Dec. 09. Failing that
(since proofing and typesetting takes a long time!),
it will appear no later than March of 2010.

I apologize for its lateness — a lot of people are looking forward to it and
I don’t like to keep people waiting. Rest assured that
I’m working as quickly as possible and hope to present something that you
(and all fans of the other books) will really love.

Feel free to share this information with others who are wondering about
what’s going on.

Sincerely,

Jeremy Silman

PS: I am also hoping to offer a limited hardcover version of this book!"

Thanks for the update. I was going to buy the 3rd edition, literally this week, but now I think I'll wait!

I'd still suggest buying the 3rd edition. It seems the 4th will be quite different, and I'll bet the older one will still pack value.