This is the 7727th most frequent German word.
handbüchern
"Handbüchern" means "manuals" or "handbooks" in English.
The word 'Handbüchern' is used as a plural dative noun for 'manuals,' indicating where information was found.
Ich habe viele hilfreiche Informationen in alten Handbüchern gefunden.
I found a lot of useful information in old manuals.
Here, 'Handbücher' is in the nominative plural form, referring to the subjects that contain instructions.
Die Handbücher dieser Maschine enthalten genaue Anweisungen.
The manuals of this machine contain precise instructions.
The word 'Handbücher' is used in the accusative plural form, representing the object to examine.