The ‘Wartime nickel’ honors Thomas Jefferson the 3rd U.S. President and his plantation villa 'Monticello' designed by Jefferson himself. This nickel is also a symbol of the many sacrifices and hardships that Americans had to endure during the Second World War, 200 years after Jefferson's time. This five cent coin released between 1942 and 1945 has Jefferson's profile in the obverse and ‘Monticello’ in the reverse. Interestingly, the Wartime nickel had no Nickel in its composition! It was composed of 56% Copper, 35% Silver and 9% Manganese. That’s why it is also called the ‘Silver nickel’.
Why Jefferson for the nickel?
Thomas Jefferson, the principal architect and the mind behind the famous words ‘…all men are created equal…’ in the ‘Declaration of Independence’ is hailed as one of the best Presidents of our country. He is known for his consistent support for the emancipation of slaves, his efforts for the Lewis-Clark expedition for mapping uncharted territory towards the west, the bold move to purchase Louisiana from the French, his architectural ventures for his villa, Monticello and the University of Virginia and his many inventions. So when it was time to change the nickel's design, it is no wonder that his profile was chosen for the obverse.
The earlier Buffalo nickel (1913 – 1938) design while considered great now, wasn’t very popular during its days. (More about the Buffalo nickel here) As in those days, a design could be changed every 25 years, the U.S. mint got ready to modify the unpopular Buffalo nickel in 1938. With the bicentennial of Thomas Jefferson’s birth anniversary coming nearer, the U.S. mint decided to release a new nickel design in his honor. A design competition was announced in January 1938 with the Mint director Nellie Tayloe Ross and three other sculptors as judges. Felix Schlag of German descent won $1000 for his design of the five cents or the ‘nickel’ as it was called. 
Jefferson nickel vs. Wartime nickel design
Initially when it was released in 1938, the Jefferson nickel was composed of 75% Copper and 25% Nickel. During the Second World War, Nickel was an important metal that was used in alloy compositions in armor plating and in jet engines and had to be conserved. The U.S. mint needed an alloy not made of Nickel yet something that could satisfy counterfeit detectors in vending machines, with the same weight and electrical resistance as in the original Copper-Nickel alloy. With that in mind the Wartime nickel was made with a composition of 56% Copper, 35% Silver and 9% Manganese.
As a collector there are a few things that you could observe to find if you are holding Wartime or a non-wartime Jefferson nickel in hand. The main difference is the mintmark on the reverse. While the initial and latter (i.e. non-wartime) Jefferson nickels have a small mintmark to the right of Monticello and no mintmark for Philadelphia, the Wartime nickels have a big mintmark above Monticello. The Wartime Philadelphia nickels also sport a big ‘P’ mintmark, which was the first for any Philadelphia coin.
The Wartime nickel can also be identified by it's dull gray-black color and the texture that is quite different to the non-wartime Jefferson nickels.
The Counterfeit Wartime nickels
Francis Leroy Henning, a brilliant counterfeiter created nearly half a million nickels and tried to make money out of them. He would have too, if it hadn't been for his version of the Wartime nickel of 1944! The FBI got wind of him through counterfeit 1944 nickels that didn't have the big mintmark as was expected of a wartime nickel of that date. But strangely enough, even though its illegal, the Henning nickels are sought after by collectors!
Some rare Wartime nickels
The 1943-P nickel with a 3 stuck over 2 sells for around $600 at MS-65 conditions. Some 1943-P nickels that have a Doubled eye (Jefferson's eye appearing twice, one below the other) sell for over $350 at MS-65. 1945-P nickels with a Double-die obverse sell around $300 in Mint-state conditions. Other mint error coins like some 1942-P and 1943-P coins struck in the original Copper-Nickel alloy are also considered rare.