Well...what you've got to realise with Asimov is that many of his works/series started out completely unconnected but years later he revisited these and started adding to these series in ways that would tie them all together.
Thus, the original Foundation trilogy written and published in the 50's ("Foundation", "Foundation and Empire" & "Second Foundation") do stand alone and can be read without having read anything else prior to these. They portray a time far into our distant future when mankind has colonised the Galaxy but now this empire is about to break down.
Similiarly, the first two Elijiah Bailey novels were published in the 50's and they had no connect with any other books. In the early 80's, Asimov revisited the Foundation series adding sequels ("Foundation's Edge" and "Foundation and Earth") and prequels ("Prelude to the Foundation" and "Forward Foundation"). He also added sequels to the Elijiah Bailey novels ("Robots of Dawn" and "Robots and Empire"). These new books began to tie the two series together, along with as with "I, Robot" and the various Galactic Empire novels ("Pebble in the Sky", "Currents of Space", "The Stars, Like Dust"), a rich tapestry of our future history is formed.
The "I, Robot" stories are supposed to be set in our immediate and near future. The Elijiah Bailey novels are set in Earth's more distant future in which mankind has just begun to colonise the galaxy. The galactic empire novels were set much later still, during the height of our galactic empire and the foundation stories come much later again, as this empire begins to collapse.
You could try to read these in chronological order but it's not necessary and I'm not even sure it's even desireable.
