For connectors, you need 1 clip set (2 connectors and 2 plastic insulators) for each single strip of heat tape. The wire is just that: an extension cord with the head cut off and plug intact. Say your book shelf has 5 shelves at 3' each across. You would need 15 feet of heat tape, 1 roll of aluminum tape, 5 clip sets and 5 wires. Then you need a powerstrip and a rheostat to plug it all into. Does that help answer your question?
Just keep walking and ignore the monkeys...