Sometimes you might want to display only your popular posts from your “Featured” category, or your “books” category. Use this snippet to achieve it.

 
<?php 
$args=array( 
'cat' => 3,
'orderby' => 'comment_count',
'order' => 'DESC',
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => 6,
'caller_get_posts'=> 1 
); 
$my_query = null;
$my_query = new WP_Query($args); 
 
if( $my_query->have_posts() ) { ?> 
<ul> 
<?php while ($my_query->have_posts()) : $my_query->the_post(); ?> 
<li><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></li> 
<?php  endwhile; ?> 
</ul> 
<?php } 
 
wp_reset_query(); ?> 

Remember to change this line to the category you want:

 'cat' => 3,

And set this line to how many posts you want to display:

 'posts_per_page' => 6,