FIG. 1 is a perspective plan view of a book bag showing my new design;
FIG. 2 is a front plan view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is an elevational view of one side thereof;
FIG. 5 is an elevational view of an opposite side thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines in all views indicate stitching and form part of the claimed design.