For new unknown writers it is extremely difficult to get published by large publishing companies They have thousands of submissions in a year, out of which, they select a small percentage for publishing.
Print On Demand, POD, publishers are relatively new, using low cost electronic printing methods is an alternative to get published. But the writer has to pay up-front fee for setup, and may end up with a few samples of his work. Thee writer is not supported beyond that and must promote and sell his/her book on his own.
The best solution I found for myself is self-publishing for the lowest cost and most effective method getting published. The examples of successful self-publishers in this booklet could be inspiring, and the techniques cover the details, including ISBN and trade marks.