These days, stories in comic books are so darn decompressed that you're lucky if you get a single significant development over the course of twelve meandering issues. However, back in the 1960s, major events occurred at a much more frequent – and arguably more satisfying – pace.
In the first issue of Stan Lee and Jack Kirby’s The Avengers, Iron Man, Thor, Hulk, Ant-Man, and Wasp banded together to defeat Thor’s mischievous brother, Loki (sound familiar?). By issue four, Hulk had left the team and the Avengers had discovered Captain America’s long lost body, buried deep beneath the arctic ice. Then, by issue sixteen, Iron Man, Thor, Wasp, and Ant-Man (now known as Giant-Man) had left the team to be replaced by former villains Hawkeye, Quicksilver, and the Scarlet Witch.
The original Avengers stories would probably come off as a bit “unrefined” to readers with more modern sensibilities, but they did depict a number of the iconic Avengers moments that will likely feature prominently in the forthcoming feature film of the same name – and thus they're invaluable for understanding what makes The Avengers in its many forms so very special.