From the InDesign book palette, select “Export Book to PDF” using the same preset for creating your press-ready PDF.
Open the PDF in Adobe Acrobat Pro and save it as an html file (File> Save As> More Options> HTML Web Page). Before saving, click the “Settings” button and uncheck "Include Images" and "Run OCR." Click “OK.” Saving the PDF as a Word file does not capture all of the text in the headers properly.
Save the html version of the PDF file where you can locate it. Open the html file in MS Word and save it as a .doc file. Now, follow the directions outlined in the “Proofreading” post.