LR vs. LR5
I have several books of LR4:Kelby,Evening etc.
Is LR5 sufficiently different from LR4 that books such as these would not be useful in learning LR5?
I don't believe so, the differences between the two can be picked up on places like youtube or even on Adobe TV: www.tv.adobe.com
I have several books of LR4:Kelby,Evening etc. Is LR5 sufficiently different from LR4 that books such as these would not be useful in learning LR5?
Absolutely not. The basics of using LR is in the book that you have.
As for LR5, yes, it has several new features. Have you looked at the videos showing the new features? They are very easy to locate if you take the time to use Google or whatever is the search engine of your choice.
There's a huge leap in how Lightroom handles high iso sensor noise, the radial tool (which is new) perspective controls that rival DxO perspective corrections, Offline Editing capabilities (if you take your workflow away from your desk you can still edit if you are disconnected from your network and do not happen to have the original file to edit from).
There are plenty of reasons to upgrade from 4 to 5 for me. You should check it out yourself by downloading the free trial.