Vernon's Annotated Constitution of the State of Texas
Without question, this three-volume set is the most detailed and up-to-date resource available to research the Texas Constitution of 1876.
As reflected on the publisher's website, three of the nine books were published in 2018 and the remaining six were published in 2007. However, each book is updated annually with a so-called "pocket part."
The preface to Volume 1 provides a good overview of the substantive content of the entire set of books.
For example, the preface describes the included "Notes of Decisions" in the following terms: "This feature, the distinguishing hallmark of Vernon's Texas Codes and Statutes Annotated, consists of a thorough treatment of judicial constructions of the Constitution, by both the federal and state courts, as well as opinions by the attorney general."