Written by Jack Coombe this was the first book I read specifically about the war to the west. Don't know how successful this book was commercially but I learned a great deal about Vicksburg and have to agree with many who believe this to be a major turning point in the war. The Union engineering efforts to take Vicksburg(unsuccessful) were very interesting to read about as well.
____________________ "When war does come, my advice is to draw the sword and throw away the scabbard."
General Thomas J. Jackson
If you like reading about Vicksburg, beg, borrow or steal a copy of "98 Days." Grabau. Although some will say that it is not the last word on Vicksburg, it is close enough. The 98 days are counted down from when Grant crossed the river.
Also try "Triumph and Defeat" vols. 1 and 2 by Terrence J. Winschel (current chief historian at Vicksburg National Military Park). Ed. C. Bearss 3 volume set is considered by many folks to be the most comprehensive study to date, but it will set you back a $100+...I have yet to take the plunge on that one myself. I was once quite the eastern theater buff until I began reading about the west. There are so many colorful characters and fascinating events to be found. I honestly haven't read anything other than western/trans-Mississippi subjects in over a year.