What do we learn about Jacobs’s intended audience from her “Preface by the Author” and L. Maria Child’s “Introduction by the Editor”?

We learn that Jacob's intended audience was the women of the North, as well as all people living within the free states.

I have not written my experiences in order to attract attention to myself; on the contrary, it would have been more pleasant to me to have been silent about my own history. Neither do I care to excite sympathy for my own sufferings. But I do earnestly desire to arouse the women of the North to a realizing sense of the condition of two millions of women at the South, still in bondage, suffering what I suffered, and most of them far worse. I want to add my testimony to that of abler pens to convince the people of the Free States what Slavery really is.