Some time around this period of time,in early Christianity, somebody got the big idea, "Hey,let's cut up the scroll into pages, and sew the pages together. And then,put it all in a book.

大概在这段时期，在早期的基督教里，有人想出了一个好主意，即把书卷断成张页，并用线一张张连起来使之成书。

耶鲁公开课 - 新约课程节选

It just means pages sewn together and placed within the covers of a book.

意思是连起来的张页,外面是抄本封面。

耶鲁公开课 - 新约课程节选