title_body: As a US citizen is it illegal to access an ebook from a country where it is PD, if it is not PD in the US?
upvoted_answer: Assuming the US Citizen is in the US then almost always yes it is illegal.
  
  
    Downloading a copy for personal use to an ebook device while in the US
  
  
  Yes the US copyright law prohibits the downloading of works that are protected by copyright in the US from foreign servers that do not have permission to distribute the copyright protected material in the US.  This is part of the Title I of the DMCA.
  
  
    Reading a copy of the ebook from a server in PD country without
    downloading (i.e. html only)
  
  
  Technically you are still downloading the text.  The HTML Files are stored on your local computer in your Temporary Internet files. This would be in violation of the DCMA.  In theory if you remote in to a computer in another country and read it, they there would be no violation of the DCMA.  However if you are remoting into that server specifically to evade US law then you are in violation of other statues involving international crime.
  
  
    Opening a copy of the eBook from a server in PD country without reading
  
  
  This is going to be dependent on if the text gets stored in non volatile memory on your computer.  If it creates temp files with the text on your hard drive then technically it would violate Copyright in the US under the DMCA.  If it is only putting the text into memory then it is not actually creating a copy of the document.  So it does not violate the DMCA unless there is a way to save the text on your local device in which case it would be a tool capable of circumventing Copyright.  In which case the use of the tool is a violation of DMCA even if it is not used in this manner.