There are really four dimensions, three which we call the three planes of Space, and a fourth, Time.
Book #3 of 20 in the SDE Classics Science Fiction Collection
When an English Scientist, known only as the Time Traveller, invents a machine that can travel through time, the most logical outcome would be to test such a machine. After a trial run that saw him travel three hours into the future, the Time Traveller pushes further into the future to year 802,701, where he meets a mellow race of humans called the Eloi. Soon he discovers that the Eloi are not the only human race left on earth...
A hundred years ago, novelist H.G. Wells predicted that science would be "king of the world." Titanic's Jack Dawson may take issue with that claim, but he’d have a tough time disputing the compelling influence Wells had on politics, society, and the future that extended far beyond the literary realm. Considering Wells is one the founding fathers of sci-fi (along with Jules Verne and Edgar Rice Burroughs) and the author of The Time Machine, The Invisible man, The Island of Dr. Moreau, and The War of the Worlds, that's saying something.