In my neighborhood at this time of year, yards have Halloween decorations (black cats, ghosts, grave stones, owls, pumpkins, skeletons, witches), and stores have Halloween costumes and trick-or-treat candy. These all suggest the customs currently associated with Halloween.
Browsing the Relative Index for "Halloween" yields:
The Relative Index entry without a subheading identifies the interdisciplinary number:
394.2646 HalloweenThe upward hierarchy for 394.2646 includes:
Hence the interdisciplinary number for Halloween is also the number for works that emphasize customs. Examples of works classed in 394.2646 are The Story of Halloween, The Halloween Book of Facts & Fun, and Treat or Trick: Halloween in a Globalising World. The first LCSH for all three works is "Halloween" (with the form subdivisions "Juvenile literature" for the first two, and "Congresses" for the third).
What about handicrafts? The number 745.5941646 Halloween—handicrafts is built with 745.59416 Holidays plus 46 from 394.2646 Halloween, following the add note at 745.59416. Examples of works classed in 745.5941646 are All New Crafts for Halloween and 175 Easy-to-Do Halloween Crafts. The first work has LCSH "Halloween decorations" and "Handicraft" both with the form subdivision "Juvenile literature"; the second has "Handicraft" and "Halloween decorations."
What about cooking for Halloween? Browsing the Relative Index for "holidays" yields (among other things):
The record for 641.568 Cooking for special occasions has the class-here note: “Class here cooking for holidays, for parties.” Since there is no subdivision for Halloween, works on cooking for Halloween are classed in 641.568. Examples are Wormy Apple Croissants and Other Halloween Recipes and Betty Crocker Halloween Cookbook. Both works have the first subject heading "Halloween cooking" (with the form subdivision "Juvenile literature" for the first work).