No need to worry about that one.  Looking at Wikipedia&#x27;s list of volume&#x27;s, looks like distributed systems are not being covered.  But I agree with you anyway.  Let&#x27;s quote the man himself (taken from his website): &quot;As I continue to write Volumes 4 and 5, I&#x27;ll need to refer to topics that belong logically in Volumes 1--3 but weren&#x27;t invented yet when I wrote those books&quot;.  He plans to complete Volume 5 by 2025.  Tune in ten years from now to see how it goes.