Islamic Jurisprudence According to the 4 Schools
I bought this as its the only Fiqh book on the market discussing the 4 Schools. It helped me alot in intellectual discussions as I interact with a lot of Maaliki's and Shaafi's. The details in the book are excellent and all opinions are referenced from which source it came from.
My only critique is that such a big book should have been a Hardback edition. It is a bit flimsy when flipping pages so I advise not reading it unless you have it on a table to give it a back.