On Ward's website, he tells us the following:
'History of Science Fiction' is a graphic chronology that maps the literary genre from its nascent roots in mythology and fantastic stories to the somewhat calcified post-Star Wars space opera epics of today. The movement of years is from left to right, tracing the figure of a tentacled beast, derived from H.G. Wells' War of the Worlds Martians. Science Fiction is seen as the offspring of the collision of the Enlightenment (providing science) and Romanticism, which birthed gothic fiction, source of not only SciFi, but crime novels, horror, westerns, and fantasy (all of which can be seen exiting through wormholes to their own diagrams, elsewhere). Science fiction progressed through a number of distinct periods, which are charted, citing hundreds of the most important works and authors. Film and television are covered as well.
This is a really fascinating project and I'm not sure if copies are still available, but you could purchase a limited edition print at one point, and the link is here. And Fast Company did an interested extended post about it here. Doing a bit of a Tor UK spot, I've seen Douglas Adams, Vernor Vinge and Greg Bear. Can you see your favourites on here?