great. kovidgoyal 06-19-2009, 01:24 PM The checkers are largely useless, there is a whole host of things that could be wrong with epub files that would prevent them from displaying in various readers that the checkers wont catch. On the other hand there is another host of things that the checkers will complain about that wont cause problems in any EPUB reader. Still, fixing all the things that they complain about wont hurt, if you have the time and patience for it. bcogney 06-19-2009, 01:54 PM Kovid, This all sounds good. Since I am new to ePub, I am interested to know what the checkers will miss and what checkers might pass that the readers will complain about? Also, Are there tools/suggestions on anything else beside these "useless" checkers to help validate ePub files? Jellby 06-19-2009, 02:05 PM I don't think they are useless, Kovid. I write ePUBs manually, and the checkers help me find errors like missing closing tags, duplicate ids or out-of-sync .opf files. bcogney 06-19-2009, 02:41 PM Where can I find a detailed a list of errors that chckers can find, Jellby? kovidgoyal 06-19-2009, 02:42 PM You can use any standard XML validater to validate OPF, NCX and XHTML files against a DTD (that's really all that epubchecker does anyway). I just think that releasing tools called "EPUB checkers" that don't guarantee anything at all is rather counterproductive. People new to them are going to expect that if the tool passes their EPUB file, the file is