Another stock I have owned on and off (FEET) filed for bankruptcy today due to liquidity problems. Book Value was somewhere in the $9.00 range. I'm not making a direct comparison and am very long PZN, but thought it interesting that a stock with so much supposed book value could file for bankruptcy.
Cash Flow is most important but it can be difficult to calculate the real number. That's why PZN's stock price looks low relative to traditional measurements (FFO, Book Value). What really matters is that PZN is not generating sufficient cash to pay the dividend. They are borrowing.
The nice thing about cash flow analysis is that it tends to cut through all the accounting nonsense and games that company's play.
Still think Book Value is important? Look at Dell's. It's just over a dollar but their earnings, cash flow and growth are great. JMHO.