title: .NET Excel Library that can read/write .xls files
body: <p>I'm looking for an Excel library which reads/writes .xls (not .xlsx) files.</p>
  
  <p>I'm using <a href="http://code.google.com/p/excellibrary/" rel="noreferrer">excellibrary</a> but it's very buggy and I <a href="http://code.google.com/p/excellibrary/issues/detail?id=60" rel="noreferrer">can't seem to open the files I create</a>. The issue has been known for almost a year and hasn't been fixed yet.</p>
  
  <p>I've seen in another thread someone suggested <a href="http://epplus.codeplex.com/" rel="noreferrer">EPPlus</a>, but that only works with the 2007/2010 .xlsx format.</p>
  
  <p>I've used <a href="http://sourceforge.net/projects/koogra/" rel="noreferrer">Koogra</a> in the past, and been quite happy with it, but I believe it can only read... not write.</p>
  
  <p>If you know of a library, please let me know what it's called.</p>
  
  <p>Edit:
  I'm quite happy to create my Excel file with the built-in Microsoft.Office.Interop.Excel if necessary, however my machine has Office 2007 and the target machines only have Office 2003. I noticed I have 2 file versions for that library: 12, and 14. I checked the Excel version on the target machines and it's 11.8169.8172 - I'm assuming that the built-in Excel interop will not work on the target?</p>