The list of what is contained in a book is not the Table of Content but the Table of Contents.
The singular form content can only be used to refer to something abstract or not easily dividable into parts. For example, you can talk about the political content of a song, the information content in a book, or the alcohol content of wine (e.g., 12%).
These days, content is also used to refer to the text and pictures on websites, and content marketing is using useful articles and information on a website to attract, interest and retain new customers.
Incidentally, in Table of Contents, “Table of” is often left out, and most books refer to this section of a book simply as Contents.
© 2014 Baxter Publishing, Hilversum, The Netherlands