The process of gaining a book contract is different for every author and luck plays a role. I had just left a long-term hospital job and was at loose ends. My first thought was to write a research paper, then to write a book though the only thing I had written to that point was an essay on love which was published in my college's newspaper and a two-hundred-fifty page doctoral dissertation. But being completely ignorant of the publishing industry I trudged on, writing a one-page outline of my proposed book and its first three pages. Which I sent to the marketing director of Simon and Schuster or Doubleday, I no longer remember which, gaining their name from the phone directory (remember those?).
A month later I received an apologetic reply from him, stating that he had been traveling across the country and so been delayed in responding. He said they weren't interested in publishing my proposed book since they wouldn't know how to market it but if I wanted to write more stories like the one I enclosed they would be interested.
Feeling insulted by his delay in responding (like I said, I knew nothing about publishing) I ignored his letter. Two weeks later I was walking with a girl-friend in a Manhattan park where we met a couple she knew. The man had a degree in English from Columbia College and wrote travel articles and small pamphlets like those found in supermarkets ("Do You Know Your Wife?" etc). The only thing I knew about publishing is that one needed a lawyer to negotiate a contract, which I optimistically assumed I would get. I asked him if he knew one, he gave me her name and she who turned out to be a major figure in the publishing industry, partner in a large law firm, the past lawyer of a historic Hollywood screenwriter/novelist, and (I later read) is mentioned in the last volume of William Shirer's autobiography.
I phoned her, she asked to see the three pages I wrote, I sent it to her, she became my agent, and within two weeks I had an agent, a publisher, an editor, and a contract that required me to complete the book in a year. Terrified of failure, I completed the book in six months, it was published a year later ("Troubled Children/Troubled Parents: The Way Out") and my agent sent me the rave reviews including one from Publishers Weekly ("outstanding").