field guide vs guidebook

field guide and guidebook both are nouns.

Word	Noun	Adjective	Verb	Adverb
field guide	Yes	No	No	No
guidebook	Yes	No	No	No

As nouns, guidebook is a hypernym of field guide; that is, guidebook is a word with a broader meaning than field guide:

field guide: a guidebook describing natural objects of some type that might be encountered in the field
guidebook: something that offers basic information or instruction

Other hypernyms of field guide include guide.

field guide (noun)	guidebook (noun)
a guidebook describing natural objects of some type that might be encountered in the field	something that offers basic information or instruction