What is a good working definition of Realism based on the texts we read by these two men this week?

READ:
Realism: NAAL, Realism and Naturalism, 578.
Howells, 314-316; Editors Study, 579-583; From Novel-Writing and Novel-Reading. Brightspace>Content>Course Materials
James, From The Art of Fiction, 584-586.
Howells (The Dean of American Letters) and James are the standard bearers for Realism in American Literature.
What is a good working definition of Realism based on the texts we read by these two men this week?
Which text does the best job of explaining realism, in your opinion, and how/why does that author communicate his meaning successfully?
Why did realism become a key component of American Literature? What was happening contextually that explains why these men would argue for “truth” in writing?