Approximate size of each sewing pattern envelope is 5.75" x 8.75".  Most pattern envelopes are slightly worn, and some with tears along the top-flap.  You might find on some of the pattern envelopes that I have carefully used Scotch Tape to prevent further tears.  Once again, this is just a cosmetic issue and doesn't affect the contents.  I have not tried to remove any of the 'age-spots' on some of the envelopes; the UNCUT patterns inside are not affected.  If you have any questions, please contact me.
Pattern envelope backs have a wealth of information to help you make decisions (a detailed description of the garment, the proper number of yards of material needed, notions needed to complete your project, and types of material that are suitable to use (and those types that are unsuitable also).
These patterns were kept in a large 5-drawer horizontal filing cabinet, just like you see in cloth stores.  The envelope wear & tear comes from customers looking through the drawers for their appropriate pattern number and size.  
ALL PATTERNS BELONGED TO MY AUNT, A FINE SEAMSTRESS OF DANCE RECITAL COSTUMES FOR OVER 50 YEARS.  Patterns have been well cared for over the years and stored neatly in her sewing shop.