The 
                  summary element contains a shorter, more succinct version of the primary description in the 
                  
                     longdesc
                      element.
                  
               
The 
                  summary element contains a shorter, more succinct version of the primary description in the 
                  
                     longdesc
                      element.
                  
               
<d:summary xml:id="summary">
    <p>Figure 1.1, The Hydrologic Cycle, shows the processes involved in the water cycle, 
        including evaporation, formation of clouds, precipitation, condensation, infiltration 
        and the paths taken by the water when it has been returned to the ground.</p>
</d:summary>
    This element may contain text.
This element may contain the following children: abbr, address (phrase variant), address (block variant), annoref, annotation (phrase variant), annotation (block variant), aside, block, ssml:break, caption, char, citation (phrase variant), citation (block variant), code (phrase variant), code (block variant), d, definition, emph (text variant), emph (phrase variant), expansion, hd, xforms:input, rend:linebreak, list, ln, m:math, name, note (phrase variant), note (block variant), noteref, num, object (text variant), object (phrase variant), object (block variant), p, pagebreak, ssml:phoneme (text variant), ssml:phoneme (phrase variant), ssml:prosody (text variant), ssml:prosody (phrase variant), quote (phrase variant), quote (block variant), xforms:range, ref, its:ruby, s, ssml:say-as (text variant), ssml:say-as (phrase variant), xforms:secret, sel:select, xforms:select, xforms:select1, span (text variant), span (phrase variant), sub, ssml:sub (text variant), ssml:sub (phrase variant), sup, table, term, xforms:textarea, time, ssml:token (text variant), ssml:token (phrase variant), transition, verse and w
summary element must neither be empty nor contain only whitespace.
                        
                     http://www.daisy.org/ns/z3998/authoring/features/description/