Ademas de los profetas que escribieron y que forman parte del canon de las Escrituras, el autor habla de profetas que no escribieron. [In addition to the writing prophets represented in the canon of Scriptures, the author discusses non-writing prophets.]
The book covers a little bit of scholarly issues at the beginning, but other than that, it talks about things that you may already know if you have read the Bible previously. For me it got a little boring at the middle of the book. Nevertheless, the experience may be different for others.