title_body: Standard settings for OCR'ing and compressing a book scan
upvoted_answer: The answer really depends on your needs, time you might be willing to invest, money you might be willing to spend (for commercial software), and what you are going to do with the result (is it just for your own reading, or do you plan to distribute it).
  
  A couple of open source tools that might help you are k2pdfopt and ScanTailor.  They can both clean up scanned images, de-skew them, and crop them.  k2pdfopt can perform OCR (using the Tesseract OCR engine).  I believe they both do batch processing.  If you have MS Office, MS Word also will automatically OCR a scanned PDF and convert it to .docx format if that is helpful to you.