Book value is basically the value of a company's assets, as shown on the balance sheet, minus its liabilities. This ranks the companies in the index by the ratio of their stock price to book value.
Companies trading at high multiples of their book value top the list.
That lists the companies whose stocks are trading at the lowest multiple of their book value, often because the shares are unpopular with investors. Note how this list is dominated by resource companies. And retailer Hudson's Bay Co., whose shares have dropped by half since 1988, was trading at less than half of its book value this week.