The Galactic Empire trilogy (since these 3 books are unconnected to each other, besides taking place in the same general universe, this series can really be read in any order).The Elijah Baley series (which obliquely tells the story of Earth's first robotic forays into space).I, Robot (some lists omit this, but this is really the 'origin' story of this universe - The Complete Robot can be substituted here, since it contains the same stories as I, Robot).I always have recommended the series in the following order: I think neither the published order nor the chronological order do the series justice. This list from Prelude to Foundation (1988) is also reproduced online here. Foundation and Earth (1983) The seventh Foundation novel.Foundation's Edge (1982) The sixth Foundation novel.Second Foundation (1953) The fifth Foundation novel, comprised of 2 stories originally published in 19.Foundation and Empire (1952) The fourth Foundation novel, comprised of 2 stories originally published in 1945.Foundation (1951) The third Foundation novel, comprised of 5 stories originally published between 1942-1949.(Not in Asimov's list as it had not been written yet.) Forward the Foundation (1992) The second Foundation novel.Prelude to Foundation (1988) The first Foundation novel.Pebble in the Sky (1950) The third and final Empire novel.The Stars, Like Dust- (1951) The second Empire novel.The Currents of Space (1952) The first Empire novel.Robots and Empire (1985) The fourth (final) Robot novel.

The Robots of Dawn (1983) The third Robot novel.

The Naked Sun (1957) The second Robot novel.

The Caves of Steel (1954) His first Robot novel.

The Complete Robot (1982) Collection of 31 Short Stories about robots.

The author himself, Isaac Asimov, wrote in the Author's Note of the Prelude to Foundation that he is providing a guide for those readers that might appreciate it since the books 'were not written in the order in which (perhaps) they should be read.' Therein, he offers the following chronological order:

Isaac asimov novels