The author Douglas Adams book is far from normal and the purpose can be revealed in the text. At first the Authors purpose is to just write a book, but there is more to that. The general them of the text shows that he is trying and does make is funny, it shows he wrote it in a funny way to most likely vent from the constant down turn of events in his writing life. How ever he wrote the script first for a radio drama but then it was later for the book. He got his inspiration from getting drunk one night while celebrating a european holiday of hitchhiking. While he lay there drunk he had a copy of a hitchhikers guide to europe and when he looked up at the sky... Boom it hit him, why not have a hitchhiker guide to the galaxy? Thus the idea was born. One thing you will realize while reading it is that he probably just wrote random idea that came to him. Basicly nonesense that ties into the book for example, "For thousands of years, the mighty ships tore across the empty wastes of space...they came across - which happened to be the earth- where due to a terrible miscalculation of scale the entire battle fleet was accidentally swallowed by a small dog". The pure nonsense of this quote represents the authors purpose of making a funny story.