Despite the disaster at Ishandalwana, it all comes right in the end at Ulundi, where the Zulus unsuccessfully attack Lord Chelmsford's square anchored with artillery and gatling guns, and at the right moment, the Zulus are broken and ridden down by a charge of the 17th Lancers.
If you like 19th century stuff, there is also a wonderful little book on the Crimean War (remember, charge of the light brigade), The Reason Why, by the famous English historian (primarily 17th century) Cecil Woodham-Smith. It is every bit as good, if not better, than Douglas Southall Freeman's Lee's Lieutenants and Bruce Catton's Army of the Potomac trilogy (Mr. Lincoln's Army, Glory Road (covers Gettysburg), and A Stillness at Appomatox.
The only better and more important things to read on the American civil war are Grant's Personal Memoirs of U.S. Grant and Sherman's Memoirs of General William T. Sherman.