4th edition

    

Released on the 15 of Augest 2007 wizards coast released news that they were making a 4th edition of D&D, December of 2007 they relesed a races and classes preview book of the 4e. There was a second book that followed in January 2008 named wizard and monster the players handbook and the DM's guide released in June of 2008. 

There were multiple player handbook's that have more classes,races and other things. 

Other things that they have added to make the game more free flowing and just better in general such as 

Alignments were changed from nine to just five (Good,Evil,Lawful,Chaotic and Neutral)

Changes in spells and giving all classes a similar number of at-will, per-encounter and per-day powers. Powers have a wide range of effects including inflicting status effects, creating zones, and forced movement, requiring use of miniatures. Powers are typically used with particular types of equipment; for example, powers for the fighter class receive bonuses for certain types of weapons, while rogue powers usually require rogue weapons such as daggers and crossbows, and more magical classes can use implements such as wands