John Irving has a new novel In One Person: A Novel . I started reading him, like many people, with The World According to Garp but then I went back and read his three earlier novels in order: Setting Free the Bears, The Water-Method Man, and The 158-Pound Marriage which deal with many of the ideas that really bloomed in Garp.
John Irving has said:
In my opinion, no overview of my novels is better written or more insightful than the Introduction Terrence Des Pres wrote to Three By Irving, which published in one volume my first three novels… No such thesis written on my fiction has meant as much to me—before or since.
Irving’s official site http://john-irving.com