By Liana B. Baker (Reuters) – Sheryl Sandberg's new book "Lean In" challenges men in the upper echelons of corporate America to take more women under their wing. Sandberg is on a promotional blitz for the new book, which has been praised as an ambitious reboot of feminism and criticized as a manifesto directed to women from a privileged perch. On Tuesday, she said men need to amp up their mentoring of women, especially younger ones just starting out in their careers. …