Marrying a brother's ex-wife

Q: What is the ruling on marrying a brother's ex-wife after the end of her `Iddah (woman's prescribed waiting period after divorce or widowhood)?

A: It is permissible for a person to marry his brother's ex-wife after she finishes her `Iddah. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.