In the olden days there were no presses, and all the important scriptures were handwritten and kept in large temples. Caitanya Mahaprabhu found Brahma-samhita and Krsna-karnamrta in handwritten texts, and knowing them to be very authoritative, He took them with Him to present to His devotees. Of course, He obtained the permission of the temple commander. Now both Brahma-samhita and Krsna-karnamrta are available in print with commentaries by Srila Bhaktisiddhanta Sarasvati Thakura.