one's desk-side book; a book kept at hand for frequent reference
Refers to a personally valued book kept close for regular consultation, guidance, or inspiration. Often used in literary or reflective contexts.
For him, the Bible is his desk-side book.
This dictionary is my constant companion.
From 座右 (ざゆう, 'at one's side') + の + 書 (しょ, 'book'). The phrase follows a classical Chinese pattern and has been used in Japanese for centuries to denote a cherished reference book.