I just found out that you’re issuing a new XSLT/XPath reference thru Wrox.
I have the XSLT 3rd edition and use it every day, but I have two usability gripes that you might consider fixing if it hasn’t already been through layout and typesetting yet. They’re both related, and have to do with the reference sections:
1) Dictionary-style running-heads would make it much easier to thumb through the book looking for a particular tag or function
2) If you’re not going to start each item on a new page, then some visual demarcation, such as a bold horizontal rule, between tag/function sections would improve usability.
I plan to buy the new edition as soon as it’s available, but it would be nice if these suggestions could be incorporated. Thanks.