About Michael Kay's XSLT book

This question is for Michael Kay !

I already have Michael Kay's book "XSLT 1.0 2nd Edition, Programmer's
Reference". Its a wonderful book. It won't be flattering to say that
Its a Bible of XSLT.

I have to buy Michael's latest books - XSLT 2.0 and XPath 2.0 . But I
am doubtful about the timing.. Should I buy it now? Or should I wait
till XSLT 2.0/XPath 2.0 become W3C Recommendations. There may be
chances that some language features may change from now till it
becomes Recommendation.

What is Michael's strategy to incorporate the final language(i.e. in
Recommendation form) in his XSLT 2.0 and XPath 2.0 books. Would be
publish an errata which will be free for the now buyers? Or would he
publish an altogether new edition, which we have to buy again?

But I would say, releasing a book at this stage is a good decision, as
it will spark interest in XSLT 2.0/XPath 2.0 ..

Best regards,