How do I understand comic book continuity and 'canon'?

Comic book continuity can be complex due to decades of publication and reboots. 'Canon' refers to the officially recognized storyline. Websites like the Marvel and DC wikis are helpful, but be aware that continuity is often retconned (retroactively changed). Don't feel obligated to understand *everything*; focus on the story you're currently reading. Many modern runs are designed to be accessible even without extensive prior knowledge.