"But who shall dwell in these Worlds if they be inhabited? … Are we or they Lords of the World? … And how are all things made for man?"
–Kepler (quoted in "The Anatomy of Melancholy")
This is the sort of epigraph where we could take it apart and question every bit of it: What is "The Anatomy of Melancholy"? Who is Kepler? Who are the Lords of the World? Or what world or worlds are we talking about?
Okay, keep calm, because a lot of those questions probably don't change much in how we think about this book.
Still, let's start with Robert Burton, who wrote a long (long) book called The Anatomy of Melancholy, which was first published in 1621. Johannes Kepler (1571-1630) was an astronomer. He had bad eyesight but was kind of a math whiz, so he had to rely on other people to look at the sky and tell him what was going on. He came up with a bunch of mathematical laws for how planets move that we still use today. For more on Kepler's role in astronomy, here's a helpful introductory podcast So, Burton is quoting (well, condensing) something that Kepler asked, which was about possible life on other planets. Part of Kepler's quote is just asking if there is life out there in space, which clearly relates to The War of the Worlds.
But Kepler isn't just asking, "Is there life out there?" He also seems to be asking if there might be other life down here, on Earth. Notice that "Lords of the World" puts "world" in the singular – we're only talking about one world here. In that way, this epigraph also seems to be asking who is in charge on Earth. Which is one of the issues that Wells plays with in The War of the Worlds. That is, Wells talks a lot about power in this book, whether that's Martian control over humans, or human control over animals, or (possibly) God's control over us all.