| Title | Test
                    Find
                    
                    Pattern Title | 
            
                | Expression | ^\d{9}[\d|X]$ | 
            
                | Description | A very simple ISBN validation expression - it just checks for a 10 digit number where the last digit could also be a capital 'X'.  Complete specs for ISBN available here:
http://www.isbn.org/standards/home/isbn/international/html/usm4.htm.  An enhancement would be to allow exactly 3 or 0 hyphens or 3 or 0 spaces, since these are also valid formats. | 
            
                | Matches | 1234123412 | 123412341X | 
            
                | Non-Matches | not an isbn | 
            
                | Author | Rating:
                        
Not yet rated.
                    Steven Smith | 
            
                | Source |  | 
            
              | Your Rating |  | 
        
    
 
    
    
     
        
                
	                Title: Not quite perfect ...
	                Name: Luke Arms
	                Date: 7/15/2004 2:52:36 AM
	                Comment: 
I might be wrong here, but doesn't this pattern allow something like:
123456789|
I think it needs to be:
^\d{9}[\dX]$
:)
                
                
            
                
	                Title: Should've mentioned...
	                Name: Darren Neimke
	                Date: 3/14/2004 7:02:51 AM
	                Comment: 
I've got a more comprehensive ISBN pattern here:
    http://localhost/RegexLib/REDetails.aspx?regexp_id=487
The comments for that pattern also contains a link to some stuff which I blog'ged about ISBN's some time ago.
                
                
            
                
	                Title: Simple but nice
	                Name: Darren Neimke
	                Date: 3/14/2004 6:42:18 AM
	                Comment: 
Like it Steve, this would certainly fall under the 80/20 rule.