The proven Zacks Rank system focuses on earnings estimates and estimate revisions to find winning stocks. Nevertheless, we know that our readers all have their own perspectives, so we are always looking at the latest trends in value, growth, and momentum to find strong picks.Of these, perhaps no stock market trend is more popular than value investing, which is a strategy that has proven to be successful in all sorts of market environments. Value investors use fundamental analysis and traditional valuation metrics to find stocks that they believe are being undervalued by the market at large.On top of the Zacks Rank, investors can also look at our innovative Style Scores system to find stocks with specific traits. For example, value investors will want to focus on the "Value" category. Stocks with high Zacks Ranks and "A" grades for Value will be some of the highest-quality value stocks on the market today.Cornerstone Building (CNR) is a stock many investors are watching right now. CNR is currently holding a Zacks Rank of #1 (Strong Buy) and a Value grade of A. The stock is trading with a P/E ratio of 13.18, which compares to its industry's average of 20.94. Over the last 12 months, CNR's Forward P/E has been as high as 224.26 and as low as -12.92, with a median of 14.45.Investors should also recognize that CNR has a P/B ratio of 4.63. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. CNR's current P/B looks attractive when compared to its industry's average P/B of 4.86. Within the past 52 weeks, CNR's P/B has been as high as 5.36 and as low as 1.58, with a median of 3.05.Value investors will likely look at more than just these metrics, but the above data helps show that Cornerstone Building is likely undervalued currently. And when considering the strength of its earnings outlook, CNR sticks out at as one of the market's strongest value stocks. Breakout Biotech Stocks with Triple-Digit Profit Potential The biotech sector is projected to surge beyond $775 billion by 2024 as scientists develop treatments for thousands of diseases. They’re also finding ways to edit the human genome to literally erase our vulnerability to these diseases. Zacks has just released Century of Biology: 7 Biotech Stocks to Buy Right Now to help investors profit from 7 stocks poised for outperformance. Our recent biotech recommendations have produced gains of +50%, +83% and +164% in as little as 2 months. The stocks in this report could perform even better.See these 7 breakthrough stocks now>>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Cornerstone Building Brands, Inc. (CNR): Free Stock Analysis Report To read this article on Zacks.com click here.