HeinOnline is a great place for online research in early English law. If linking through the law library's database, the first screen on the HeinOnline website has a list of "Subscribed Libraries." About two-thirds (2/3) of the way down (arranged alphabetically) is a link titled "Selden Society Publications and the History of Early English Law" (See picture below). Click on this link.
Once you clicked on the above described link, you should see a menu at the top of the page. That menu should look exactly like the one shown in the below picture. This menu grants you access to a number of great resources that you should definitely explore. Among those resources is the "English Legal history Classics" link. That link will grant you access to numerous scholarly works by such jurists as William Blackstone, Learned Hand, and Henry de Bracton. In the picture the link to the "Selden Society Publications" is circled in red. This is because the Selden Society Publications are a great resource and one easily negotiated. Additionally, the Selden Society publishes case reporters for cases dating back to before the year 1200. Click on that link.
Once you have clicked on that link you will see a list of Selden Society Publications. The third (3rd) one down is called the "Selden Society (Annual) Series." This series contains the "select cases" type volumes, the "Year Books Series" volumes, and many other types of volumes.
First, it is important to note that case reporters as we understand them are relatively new in the field of law. In the earliest periods, any document dealing with a case was a sealed record. Additionally, there were no official reporters. As such, reporters containing cases from those times draw their materials from other sources. In the earliest periods, the only material available were the notes of law students/apprentices who were observing the trials. Later, these materials were supplemented or replaced with the notes of judges and counsel. This continued until the first official reporter in England was adopted in 1865. The important note here is that as you read cases from various centuries, the style of case reporting will vary widely.
The "select cases" type volumes are those volumes that are titled similarly to "Select Cases in the Court of King's Bench Under Edward I." These types of volumes are exactly what they sound like. They are selected cases from the King's Bench during the time of Edward I, or whatever time period the relevant volume covers. These volumes contain various indexes. These include an Index to Statutes Cited, an Index of Names and Places, and - most importantly - an Index of Matters (also called an "Index Rerum"). The Index of Matters/Rerum is a topical index allowing you to locate cases dealing with a particular topic, e.g., Novel Disseisin.
The "Year Books Series" are organized by year, each volume usually representing only one or two years during the reign of a particular king. These books are unique in that they include a "syllabus" (editor's explanation of the case - similar to Westlaw) before each case. These volumes also contain various indexes and tables. Commonly included are a Table of Statutes, Table of the Forms of Action, Table of Cases, Index of Persons and Places, and an Index of Matters.
Other types of volumes in the Selden Society Publications are those dealing with particular types of courts, pleas, and rolls. These volumes may deal with cases heard by a particular court, certain types of cases, or those cases recorded on a particular type of Roll (e.g., Coroner's Rolls, Curia Regis Rolls, etc...).
Early English Books Online - known as EEBO - contains many (about 125,000 books) of the most important and influential English books published between 1473-1700. In addition to this primary collection there are a few hundred additional books from after 1700. These books cover a vast array of topics such as literature, history, theology, philosophy, mathematics, science, and more. Many of these books, while categorized as as history or philosophy, are on point in doing early English legal research.
For EEBO's own research guides (i.e., how to use EEBO) Click Here.
For EEBO's FAQ Click Here.