I can't recall exactly when I read "To Kill a Mockingbird." I do recall that as for many of you, it was required reading at some point in my education. I also remember its raw and layered portrait of the Jim Crow era South – told through the voice of a child – resonated with me for a long time. Harper Lee's Pulitzer Prize-winning work turns 50 this weekend. Unfortunately I have forgotten some of the key plot twists, and thought this might be a good time to re-read this American classic. But I have to admit I was a little surprised to find Amazon.com customers gave it only 4 out of 5 stars. Certainly a good rating, but I guess not what I expected for a cherished literary piece. I'll read it again and judge for myself. In the meantime, we'll take a few minutes on tonight's broadcast to look back on "To Kill a Mockingbird," and examine why it endures – 4 stars not withstanding – as a must-read for so many Americans.

Also, NBC News science and environmental expert Jeff Corwin is going to join us live from the Gulf to show us how scientists are desperately trying to save already endangered sea turtles from the ravages of the oil slicks now covering their habitat. We'll also have more encouraging reports coming from BP on progress being made on two fronts to both contain the leak and plug the well.

I hope you'll join us tonight for NBC Nightly News.