MSDN : TextInfo.ToTitleCase
Make sure that you include: using System.Globalization
string title = "war and peace";
TextInfo textInfo = new CultureInfo("en-US", false).TextInfo;
title = textInfo.ToTitleCase(title);
Console.WriteLine(title) ; //War And Peace
//When text is ALL UPPERCASE...
title = "WAR AND PEACE" ;
title = textInfo.ToTitleCase(title);
Console.WriteLine(title) ; //WAR AND PEACE
//You need to call ToLower to make it work
title = textInfo.ToTitleCase(title.ToLower());
Console.WriteLine(title) ; //War And Peace