"Books [and book chapters] can include comprehensive accounts of research or scholarship, historical data, overviews, [o]r experts' views on a theme or topic. Use a book when you require background information and related research on a topic, when you want to add depth to a research topic or put your topic in context with other important issues" (CQ University Library, "Evaluating Books, Journals, Journal Articles and Websites").
Scholarly books are published by university presses, such as UC Press, NWU Press, etc., but there are other publishers that also publish scholarly books. If the book has citations within the text / footnotes and a bibliography at the end of the chapter or the back of the book, it's generally scholarly. Scholarly books can be monographs or anthologies. Monographs are books written by a single author. Anthologies are books in which each chapter is written by a different author and are collected into one book by an editor.
Example
Here is a scholarly monograph I found in UC Libary Search, the library catalog, that could be potentially helpful for my investigation of the black power movement and black women: Patricia Hill Collins' From Black Power to Hip-Hop: Racism, Nationalism, and Feminism.
Use UC Library Search to find eBooks, print books, as well as articles and other materials (UC Merced Library, 6:17).
Fall 2021 Workshop Recording: Using UC Library Search (~ 9 minutes)