Previous and next entries nav – within a categeory I'm not sure what I've done, I had this working at the top of my entry.html template:



{% set params = craft.entries.section('ourWork').relatedTo(category) %}

{% set prevEntry = entry.getPrev(params) %}
{% set nextEntry = entry.getNext(params) %}

{% if prevEntry %}&lt;a href="{{ prevEntry.url }}"&gt;Previous&lt;/a&gt;{% endif %}
{% if nextEntry %}&lt;a href="{{ nextEntry.url }}"&gt;Next&lt;/a&gt;{% endif %}


For some reason I just get:
Variable "category" does not exist

The section name is correct and this does have a category field assigned.

my index template category part is:

{# Projects
---------------------------------------------------------------------------#}
&lt;div class="banner projects"&gt;
&lt;div class="row"&gt;        
  &lt;ul class="no-bullet small-up-2 medium-up-3 large-up-4 large-centered"&gt; 
  {#
  Display catgeory nav 'ourWork'
  #}
    {% nav category in craft.categories.group('ourWork').level(1) %}         
      &lt;li class= "column"&gt;                        
          {# &lt;p&gt;{{ category.WorkCategoryDescription }}&lt;p&gt; #}                 
          &lt;a href="{{ category.url }}"&gt;&lt;img src="{{ category.categoryImageThumb.first.getUrl('categoryThumbnail') }}"&gt;&lt;/a&gt;             
          &lt;p&gt; &lt;a href="{{ category.url }}"&gt;{{ category.title }} &lt;/a&gt;&lt;p&gt;
      &lt;/li&gt;
    {% endnav %}
  &lt;/ul&gt;
&lt;/div&gt;
When you are within your nav tag context, category definitely exists, even if you're using include for the first snippet you posted. If you're talking about the automatically pre-assigned variable for a single category's page, make sure the category group settings are still correct and that you are requesting the right URLs.