Is it worth to buy this book now as a reference or should I wait for the next edition that might come once .NET 4.0 is released (when?)? Do you know if it will come out any time soon?
I hear great recommendations about it, and I am considering buying it.
The 4.0 vrsion isn't likely to be out for at least another year. You have to take a stand and buy at some point (if you want to buy that is), otherwise you'll always be waiting for "the next version".
If you wait, then the next question will be "Should I wait for NET 5.0" etc. etc. Books are always going to be out of date, so either just buy it or get a subscription to Safari.
Buy the "current version" book and follow the various blogs out there for the updates and new features being added.
I assume you dont like reading online, I have seen some people get hold of a digital copy (like pdf) and print portions of it. Make sure to recycle if you decide to dump the printouts. You could take printouts from MSDN too !
I wouldn't wait for a .NET 4.0 / C# 4.0 version, especially as Essential C# 3.0 was only published relatively recently, whereas C# 3.0 has been out for well over a year. I haven't got round to reading my copy yet, but the parts of the v2 version that I read were excellent.