====2008 Early Form====

The first skill tree shown to fans was revealed in the Blizzcon demo in late 2008. No official screenshots were released, though it was seen in [[:File:Barb-juggernaut-tree08.jpg|many photos and videos]] taken from the event. Only the Barbarian's can be judged, since the Witch Doctor only had 11 skills spread over his three trees. Of the Barbarian's 50+ skills, they were arranged much like Diablo 2's skills, with three distinct skill trees, displayed on tabs in the same interface window. Each row had 3-4 skills, and there were no prerequisite skills linked by columns. To move down a row in the tree, 5 points had to be spent on each row.

The skills were not as discrete as those in Diablo 2, and there was considerable overlap between skills in different trees. It appeared that the D3 team intended players to specialize in one tree per character, and thus included skills with redundant basic functions, such as +damage, +defense, etc.

====2009 Evolution====