The author continually refers to the fact certain messages were intercepted before Dec. 7, which they were, but the problem is that the U.S. had not broken all the different codes used by the Japanese, so many of the military messages remained unread. There were plenty of clues in the codes that we had broken, i.e. the diplomatic code, but hindsight has provided a clarity that wasn't there prior to the attack.
'And I Was There' by Edwin T. Layton is required reading and contains much information on the abilities of U.S. intelligence prior to and during the first part of WWII. As the title suggests, Layton, who was the Fleet Intelligence Officer at Pearl Harbror, was indeed there. He personally knew a great number of the members of the military intelligence community both in Hawaii and in Washington and his account of the goings on prior to both the Pearl Harbor attack and Midway are real eye-openers.
When the Army Pearl Harbor Board (APHB) finished its work, included in its TOP SECRET findings were:
“The War Department had the information. All they had to do was either to give it to Short or give him directions based upon it.
...
2. On November 26 there was received specific evidence of the Japanese' intentions to wage offensive war against Great Britain and the United States. (R. 87) War Department G-2 advised the Chief of Staff on November 26 that the Office of Naval Intelligence reported the [3] concentration of units of the Japanese fleet at an unknown port ready for offensive action.
3. On December 1 definite information came from three independent sources that Japan was going to attack Great Britain and the United States, but would maintain peace with Russia. (R. 87)”
Other "clues" came from the so-called Kita Messages, decoded and known in Washington in the early Fall of 1941 - Pearl Harbor broken up into grids, light signals, ..., etc.
No other US installation had this degree of survillance.