Four Four Two (4-4-2)

Arrigo Sacchi the man who gives 4-4-2 a lot of fame

This formation was the most common in 
football in the 1990s and early 2000.

The midfielders are required to work hard to support both the defense and the attack: typically one of the central midfielders is expected to go up field as often as possible to support the forward pair, while the other will play a "holding role", shielding the defense; the two wide midfield players must move up the flanks to the goal line in attacks and yet also protect the full-backs.

Milan Sacchi

On the European level, the major example of a team using a 4–4–2 formation was Milan, trained by Arrigo Sacchi and later Fabio Capello, which won three European Cups, two InterContinental Cups, and three UEFA Super Cups between 1988 and 1995. Under Milan's example, it became very popular in Italy in the late 1980s and early 1990s.

There is two very useful types of 4-4-2 : 

Milan Ancelotti

4–4–2 diamond or 4–1–2–1–2

The 4–4–2 diamond (also described as 4–1–2–1–2) staggers the midfield. The width in the team has to come from the full-backs pushing forward. The defensive midfielder is sometimes used as a deep lying playmaker. Its most famous example was Carlo Ancelotti's Milan, which won the 2003 UEFA Champions League Final and made Milan runners-up in 2005. Milan was obliged to adopt this formation so as to field talented central midfielder Andrea Pirlo, in a period when the position of offensive midfielder was occupied by Rui Costa and later Kaká. This tactic was gradually abandoned by Milan afterAndriy Shevchenko's departure in 2006, progressively adopting a "Christmas Tree" formation.

4–1–3–2

The 4–1–3–2 is a variation of the 4–1–2–1–2 and features a strong and talented defensive centre midfielder. This allows the remaining three midfielders to play farther forward and more aggressively, and also allows them to pass back to their defensive mid when setting up a play or recovering from a counterattack. The 4–1–3–2 gives a strong presence in the forward middle of the pitch and is considered to be an attacking formation. Opposing teams with fast wingers and strong passing abilities can try to overwhelm the 4–1–3–2 with fast attacks on the wings of the pitch before the three offensive midfielders can fall back to help their defensive line. Valeriy Lobanovskiy is one of the most famous exponents of the formation, using it with Dinamo Kyiv, winning three European trophies in the process. Another example of the 4–1–3–2 in use was the English national team at the 1966 FIFA World Cup, managed by Alf Ramsey.

That’s it for now, next time we’re going to talk about some coachs who played the 4-4-2 and succeed (Alf Ramsey- Valeriy Lobanovskiy- Arrigo Sacchi- Fabio Capello- Sir Alex Ferguson – Claudio Ranieri - Carlo Ancelotti – Diego Simeone)