Complex sentence: Each edition comprises an attractive pocketbook, "beautifully packaged... in the modish style of the twelves", usually containing no more than 150 pages of relatively thin paper, on which are printed the details of between 120--190 prostitutes then working in Covent Garden.
Split into simpler sentences: Each edition comprises an attractive pocketbook, "beautifully packaged... in the modish style of the twelves". They usually contain no more than 150 pages of relatively thin paper, on which are printed the details of between 120--190 prostitutes then working in Covent Garden.