Here's a start:
- Abu Ameenah Bilal Philips, The Evolution of Fiqh (Islamic Law & The Madh-habs).
There's a pdf DOWNLOAD version available, but it contains many spelling and grammar errors.
The overall purpose of this book is to acquaint the reader with the historical factors behind the formulation of Islamic law (Fiqh), in order that he or she may better understand how and why the various schools of Islamic law (Madh-habs) came about.
- Nuh Ha Mim Keller (translated), Reliance of the Traveller, The Classic Manual of Islamic Sacred Law 'Umdat al-Salik, by Ahmad ibn Naqib al-Misri.
I found this through an Australian Islam-critical society QSociety's Mediafire page, which has it in pdf form: DOWNLOAD. I'm not sure how legitimate this download is; but the book appears authentic. (This prompted the question here: Does the book "Reliance of the Traveller" play a significant role in Islam?)
The present volume, 'Umdat al-salik [The reliance of the traveller], represents one of the finest and most reliable short works in Shafi'i jurisprudence, a school with perhaps fewer scholarly differences on rulings than others because its main resource is the recension of Imam Nawawi, the great thirteenth-century Shafi'i hadith scholar and jurisprudent who upgraded the work of previous generations in terms of the authenticity and application of hadithevidence,
- Al-Azhar University prepared The Response.
It's available as a pdf DOWNLOAD, and also available online at http://www.fixyourdeen.com/.
This book is the result of a lengthy collaboration between scholars of Egypt’s prestigious Al-Azhar University and Islamic Hotline or El-Hatef El-Islami organization. Put simply, far too simply, its aim is to contest the growing number of intolerant and/or simply mistaken legal opinions that often go unchallenged in Muslim communities today.
- As-Sayyid Sabiq, Fiqh us-Sunnah The Book on Acts of Worship
It's available online here: http://www.islamicstudies.info/subjects/fiqh/fiqh_us_sunnah/ This is available as a pdf translation DOWNLOAD of questionable legitimacy. Four out of the five separate volumes are scanned here: VOLUME 1 Purification and Prayer; VOLUME 2 Supererogatory Prayer; VOLUME 3 Zakah in Islamic Jurisprudence & Fasting; VOLUME 4 Funerals and Dhikr; VOLUME 5 Hajj and Umrah
This book deals with the fiqh questions and provides supporting evidence to them for the clear Book (of Allah), the authentic sunnah of the Prophet, upon whom be peace, and what this ummah has agreed upon.
- The website Al Islam https://www.al-islam.org/ contains a large number of books published and available for reading online. I've seen several books at Al Islam go into considerable depth in Islamic history.
Ahlul Bayt Digital Islamic Library Project ... Browse for free 1700+ books and articles about Islam and the Muslim people
Note: I'm not making judgements about these books nor their authors. They just happen to be available and I'm aware of them. You can judge for yourself.