In a mere 128 pages, Lester Del Rey tells a better story than most modern writers can in 500. Day of the Giants feels astonishingly slim next to the mammoth tomes which are de rigueur these days, but that slimness just points up the fact that most of those gargantuan books are simply padded.The book is very strongly reminiscent of the Compleat Enchanter series by L. Sprague de Camp and Fletcher Pratt. Both feature modern twentieth-century men who are unexpectedly faced with the world of Norse mythology. But while the situation was expertly played for laughs by de Camp and Pratt (the Compleat Enchanter series is rightfully considered a classic of the genre), in Day of the Giants del Rey plays it straight. Fimbulwinter has descended on the Earth, Ragnarok approaches, and two twin brothers - one a war hero, the other a farmer - have been taken up to Asgard by Loki and Thor to play a role in the final battle.The interaction of modern science with magic and mythology is always interesting. I consider one of the failures of the Harry Potter series to be J.K. Rowling's relative neglect of that topic. For example, didn't witches care about the threat of nuclear war, or or ecological collapse? Surely witches who grew up as Muggles, as Harry did, must have been aware of those dangers - so why weren't they addressed? The idea of two societies existing side by side, with one unknown to the other, has all sorts of interesting possibilities...none of which were addressed by Rowling.It's true that the issue of science vs. magic has become a cliche in modern genre fiction. But it certainly wasn't a cliche in 1959, when DotG was published.In Day of the Giants, the interaction of science and mythology is handled in a much more satisfying way (I am tempted to compare the relative page counts of DotG with the Harry Potter series, just for laughs). del Rey's handling of the characters is never awkward or clumsy. By the end of the book, I found myself more satisfied than I've been at the end of many a weightier tome.I suppose that there's no way that a 128-page novel is ever going to be reissued by a modern publisher, so Day of the Giants will remain a curiosity, only to be found in libraries and used book stores. That's a pity, because it deserves a wider readership. It's not a classic that will last for the ages, but it's a very well-written, entertaining book that many modern genre writers would do well to emulate.