noun
monograph; scholarly book; research publication
Refers to a written work that presents original research or a detailed study on a specific academic subject. Often used in academic contexts.
彼は日本史に関する研究書を出版した。
He published a monograph on Japanese history.
この研究書は専門家向けに書かれている。
This scholarly book is written for specialists.
専門書 is a specialized book for a particular field, which may include textbooks and reference works, whereas 研究書 specifically presents original research.
Compound of 研究 (research) and 書 (book, document). The reading is the standard on'yomi of the kanji.