I've been away from full time Drupal development for a couple of years and have recently returned, this time making a commitment improve my understanding of core. There's a lot of information out there on Drupal caching, but I found much of it to be fragmented and outdated (Drupal 6). I wanted to provide a more comprehensive look at Drupal 7's core caching, explaining how some of this stuff is actually working under the hood.