The amount of time and effort involved in the process of publishing a book is considerable, and this book is no exception. As only one cog in the vast machine of effort involved, it is difficult for me to fully appreciate all of the hands that have touched this edition. However, without the ambition and drive of my original co-author, Dirk Henkemans, this book would have remained an unrequited dream. His drive and perseverance taught me that seemingly impossible things, like writing a book, were not only possible, but readily attainable.
I have a real hard time following what he's trying to say there. What he's saying sounds like this to me: since there's only one cog that's involved in the vast machine of effort, it is difficult to blah blah. That doesn't make a whole lot of sense. Why is there only one cog involved in the vast machine of effort when people are publishing books?
This is what I understand now:
as only one cog in the vast machine of effort involved - there are many (cogs) people that are involved in the process of writing and publishing a book and he is just one of those cogs involved in this process. All this process is a huge effort made possible by work of a great many number of people. And then he says that it is difficult for him to appreciate the contributions other people involved in the project have made. What I still don't understand is how the two clauses are connected semantically. Why, while you're being one of the huge number of people involved in doing something, is it difficult to recognize other people's equal importance in doing it?