book of instructions vs instruction manual

book of instructions and instruction manual both are nouns.

Word	Noun	Adjective	Verb	Adverb
book of instructions	Yes	No	No	No
instruction manual	Yes	No	No	No

As nouns, book of instructions and instruction manual are synonyms defined as:

book of instructions and instruction manual: a manual usually accompanying a technical device and explaining how to install or operate it

Other synonyms of book of instructions include instructions, operating instructions.

book of instructions (noun)	instruction manual (noun)
a manual usually accompanying a technical device and explaining how to install or operate it	a manual usually accompanying a technical device and explaining how to install or operate it