"How some of the writers I come across get through their books without dying of boredom is beyond me"

This quote by William Gaddis is a humorous way of revealing his shock at how some writers can compose books without ending up being tired. He is suggesting that composing a book is a laborious and dull task, and he is shocked that some writers can handle to complete their books without becoming bored. He is likewise implying that writing a book is a difficult task, and it requires a lot of commitment and effort. This quote is a suggestion to writers that composing a book is not a simple job, and it needs a great deal of effort and commitment. It is also a suggestion to readers that the books they read are the outcome of a great deal of effort and commitment from the author.