Hello JuggleDad, Miles, Paulae & Flynn!
I have the latest wp3.0 and Atahualpa 3.5.3. My posts are under multiple categories. ie, one post might be under "South" category and also under "Active" category.

I have set the Ata Theme Option+Next/Previous Navigation+New: Keep next/prev. links on SINGLE post pages to same post category? TO = YES.

I do not have any cache running.

I have set Location of Next/Previous Post Navigation on SINGLE Post Pages to Above & Below.

Unfortunately when you choose say http://ibooktravel.com.au/category/n.../south-island/ (all "south" tours) then click a post, the navigation shows "North" posts...

I then installed "Hikari Category Permalink" and set the 'default' category on all posts to either north, south or both, but it still displays 'North' tours in the next/previous navigation.

The Version Change Log for Ata 3.4.6 states:
DONE: RFE: next/previous - keep it to current category - several requests see
http://forum.bytesforall.com/showthr...vious+category
http://forum.bytesforall.com/showthr...vious+category
http://forum.bytesforall.com/showthread.php?t=3690

but this is not working for me. Do any of you have experience with this? Do I need to try again with 'Smarter Navigation' plugin, eg put 'previous_post_smart()' in the theme files?
Regards, Joan

That is most likely caused by the fact you have multiple categories for the posts. The Next/Previous goes to the next post with that has any categories in common. I don't know how you would change that functionality.

Oh dear, what a shame to be able to post under multiple categories, but not to be able to navigate through the categories.
I thought that was the whole point of the requests below, which have been ticked as "DONE".
Hopefully it will be possible with some coding. Thanks for your time Miles. Regards, Joan

Thanks for that tip STB. That's what makes this forum great. Let us know how it works for you Joan.