Alien has brought up a marvelous first topic for our group to test its teeth.
There have been many biographies written about the Professor and more seem to be published every day. ‘JRR Tolkien - a Biography’ written by Humphrey Carpenter and published in 1977 is still the one most widely read, I believe.
Sad to say, I have not read any of the biographies. Carpenter’s bio is on my list as is ‘The Letters of JRR Tolkien’ - edited by Carpenter. However, they wait in line behind ‘The History of the Lord of The Rings’.
I would like to recommend an on-line coursee offered by Barnes & Noble University entitled ‘Lord of the Rings’. The course examines the life of JRRT as a preamble to its discussion of LOTR and the Hobbit. The course started on Sept 10 although I think enrollment is still possible. If not, given the popularity of the course, it will be given again in the near future. Best of all, it’s free. Here’s a link to BNU: barnesandnobleuniversity.com/
I would also recommend that a first step in learning about the life of JRRT might be taken at the Tolkien Society’s bio page:
Tolkien, himself, spoke many times and very strongly about the relevance of an author’s personal history to the appreciation of an author’s work. It was his considered opinion that the story of the author should be thought of as inconsequential to the author’s story. I believe that this view arose from his scholarhip of ancient texts. Though most, if not all, are of unknown authorship, the Professor had nevertheless experienced the power of the tales told. I’m sure that his hope was that his own tales of Middle-earth would take their place in the literary tradition of mankind along side Beowulf and the Kalevala. Thus, his stories would become mankind’s stories, surviving far longer than the accounts of his own life.
As for your question, Alien, about whether or not JRRT had envisioned his saga ‘LOTR’ when he wrote ‘The Hobbit’, putting it simply, he did not.
To toot my own horn, my most recent article at suite101.com/welcome.cfm/tolkien discusses in part the beginning stages of Tolkien’s writing what was to be simply a sequel to ‘The Hobbit’.