From: "Yuji Kukimoto" 
Here are the typos I found in the IWLS book.

p76, 3.3.3, the 2nd line from the bottom: SPDFs -> SPFDs
p73, The paragraph starting with "Observability.."
  Observability don7t caresobservability don't cares
  (must have been introduced by an index here)
p305, [10] Clarc -> Clark, McMillen -> McMillan
p.433, [14] Pilaggi -> Pileggi