'Umdat al-Salik wa 'Uddat al-Nasik (Reliance of the Traveller and Tools of the Worshipper) is perhaps the finest single volume of fiqh available in English. It was originally written by Ahmad ibn Naqib al-Misri over 600 years ago. It was translated by Nuh Ha Min Keller into English and first published in 1991. It presents the rulings of the Shafi Madhhab, a school, which according to the introduction, probably has fewer differences within it than the other schools of Sunni Islam. I find it to be an invaluable reference as it helps me to understand the Qur'an and Sunnah though my knowledge of Arabic is deficient. It has a clear index on rulings, and helpful biographies near the end of a number of notable people.