The Dauntless came about because of a requirement for a dive bomber. Its first flight was in 1940 and was introduced to the fleet in 1940. In 1941, an improved version with armor, self sealing tanks and more machine guns was introduced.
The plane's first serious action was in the Battle of Coral Sea where Dauntlesses sank the carrier Shoho. This battle was famous because it was the first Naval battle fought entirely with aircraft.
The Dauntless made its mark during the Battle of Midway. After the bombing of Tokyo by B-25's that flew off the USS Hornet, Admiral Yamamoto wanted to destroy the US Fleet once and for all. To this end, he developed a two pronged attack. One of the prongs would attack the Aluetians in order to draw the US Carriers up there. While the Carriers were distracted there, Yamamoto planned for the other group to attack Midway and hopefully (for him) would destroy the US Fleet.
There was a slight flaw in Yamamoto's plan, namely that the US knew his intentions. Just before Pearl Harbor, the US had broken the Japanese diplomatic code because of this they knew the Japanese were up to something but they weren't quite sure what. The Japanese Naval code was a little more difficult and it was broken shortly after Pearl Harbor. The US knew that the Japanese were planning to attack somewhere with the code letters of "AF" but they didn't know where "AF" was. In order to figure this out, the Navy had all the bases transmit that they had different problems. When the Japanese stated that "AF" was short of water, the US knew that "AF" was Midway.
The Japanese were pretty much going into the Battle of Midway blind. They had thought they sank the Yorktown and badly damaged the Enterprise or Hornet (I forget which and I'm trying to do this from memory) at the Battle of Coral Sea. It turns out that the Japanese had badly damaged the Yorktown but the Yorktown was able to limp back to Pearl Harbor. Nimitz wanted the Yorktown repaired and miraculously, the crews of Pearl Harbor were able to get it repaired within 72 hours.
The main Japanese group had four carriers vs. the three US Carriers. The US had a good idea of what they were up against and were able to position their carriers in the perfect spot to defend Midway from the Japanese attack. The Japanese struck at Midway first and inflicted some pretty serious damage and were planning to launch a second wave but at the time they found out where the American Fleet was. This would prove fatal.
The Americans had a pretty good idea of where the Japanese Fleet was but they couldn't quite locate them. Through a stroke of luck, they were able to find the fleet just as the planes were about ready to return to the American Carriers because they were almost out of fuel. It was originally planned that the groups would hit the Japanese Carriers at the same time but some uncoordination didn't allow that to happen. The American Torpedo bombers struck first and in a charge were destroyed by the Japanese Air Cover, this meant that they didn't see death lurking in the skies above the carriers.
With the Japanese CAP drawn away, the Dauntlesses were able to strike. In a matter of minutes, three Japanese carriers would be littering the bottom of the Pacific. The fourth carrier would join them a little while later. This action would be where the tide in the Pacific turned as Yamamoto withdrew the rest of his force.
The Japanese carriers probably wouldn't have sank so easily had they not had fully loaded planes on the decks. So their indecisiveness from lack of knowledge helped in their demise. The Americans did end up losing the Yorktown, so Midway wasn't a victory without loss.