A cylinder unscrews itself on Horsell Common in Surrey while the astronomer Ogilvy watches, and by nightfall the thing inside has burned a deputation carrying a white flag where it stood, with an invisible heat-ray. Within days the tripods are striding toward London, firing canisters of poisonous black smoke, and red weed is spreading over the ruins. Wells's narrator is never named and files it all in the flat voice of a reporter. Know the shape before you start: a long stretch hands the story to his brother fleeing London instead, three straight chapters of Book Two are two men buried in a wrecked scullery, and the longest chapter of all is one soldier on Putney Hill explaining his plans.
The War of the Worlds is 60,044 words. At an average adult reading pace of 300 words a minute that is about 3 hr 20 min, or roughly 2 hr 30 min if you read quickly and 5 hr at a more deliberate 200 words a minute.
That count is measured from the complete public-domain text rather than estimated from a page count, so you can compare all the books side by side.