"As events evolved, we recognized that, despite our suspicions, it was very difficult to definitively identify a bubble until after the fact--that is, when its bursting confirmed its existence."
Alan Greenspan, 30th August 2002
"finding ways to identify bubbles and to contain their progress would be desirable, though history cautions that prospects for success appear slim."
Alan Greenspan, 19th December 2002
Maybe I'm just being cynical but I can't help thinking how fortunate it is for the former Fed chairman that his sudden ease in identifying bubbles has coincided with the need to sell copies of his book.
Not saying he does not have some relevant points to make, but maybe a pinch of salt would be warranted.