By David Sterman We're now in a "stock picker's market." The major averages are now moving sideways after a sustained two-month upward move, which means that stock selection becomes ever more crucial. In this kind of trading environment, it pays to see what's working. Insights into why certain stocks are sharply rising while most stocks stay in a range can help sharpen your understanding of investor psychology and sector catalysts. With that in mind, here's a look at four small cap stocks (members of the Russell 2000 Index) that have risen at least 50% in the past month.