A good treatise is an invaluable starting point for legal research because you are reading an expert's in-depth discussion of a legal topic. This can provide context and a framework for your research, and it can also point you to important statutes and case law.
See below for a selection of some of the major criminal law, criminal procedure, and evidence treatises. A search in your library catalog may lead you to many more resources, as can browsing the criminal resources on platforms like Lexis and Westlaw.