Covid-19: For updates and resources, head to UT's Protect Texas Together site.
Annotated code handbooks by subject are collections of statutes that provide the text of the statute as well as notes on court decisions and possibly secondary sources. (They may also be known as deskbooks or sourcebooks.) These summaries are helpful in providing some context to the statute and also highlighting parts of the code that have been controversial since their inception. Unannotated versions also exist and can be helpful as a one stop shop for primary authority, but of course, lack additional benefits that come with annotations.
Annotated code handbooks are similar to the USCS, USCA, and Vernon's, except that, being a handbook, it is just an excerpt from a full code, with a focus on a particular area of law like family law or intellectual property law. Depending on the subject of the handbook, there may be excerpts from multiple jurisdictions. These handbooks are intended for specialized practitioners and are usually soft-bound volumes updated on an annual basis by a new edition or not long after a legislative session from a relevant jurisdiction has ended.
Annotated codes handbooks by subject are a kind of ready reference tool. The idea is that a specialized practitioner will have a personal copy at his or her desk and carry it to court to help deal with any questions that may arise away from the office. When a major research project arises, a practitioner may consult a handbook before turning to more extensively annotated codes like USCS or USCA.
Annotated code handbooks by subject are generally a print only option, mainly published by Lexis and Thomson Reuters. (O'Connor's is most well-known in Texas, and is now owned by Thomson Reuters.) As with any research project, it can be helpful to consult a law librarian to check the availability of different subject handbooks, check a publisher's website, ask fellow practitioners in the area, or look for a research guide.
If a researcher does not already have a specific citation to look up, there are two main print tools: a table of contents and an index. Different versions of the same code provide different features to navigate the handbook. For instance, an O'Connor's handbook usually includes a "What's New" section to alert you to changes since the last edition.
If you are researching in an area that mainly involves statutory law, then a handbook is more user-friendly than looking within a larger statutory set.
As is true of all print materials, handbooks lack online citator tools such as Lexis' Shepard's and Westlaw's KeyCite.
Be aware that there is a time gap from when new legislation is passed and when a new edition of an annotated code handbook by subject is published. Educating yourself about the practices of relevant juridictions can help mitigate the harm in this inevitable delay. For example, the Texas legislature meets every odd numbered year on the second Tuesday in January for 140 consecutive days. Keeping track of when the Texas legislature has met will help you use any given edition of an annotated code handbook by subject with the appropriate caution.