Well, Dewey has finally made it into the greatest reference source on the Web! No, we're not talking about Google or Wikipedia (Dewey made it into those minor institutions years ago). We're talking about this news item yesterday in the Onion -- which not only mentions Dewey, but also mentions the Editorial Policy Committee.
And where is the "phantom zone" that they talk about, i.e., "the phantom zone between Jenny McCarthy’s book of marriage tips and novels in which a cat helps solve a mystery"?
Well, Jenny McCarthy’s book of marriage tips would not go in 306.81 Marriage and marital status, but in 646.78 Family life, since that's the part of the classification about how to have a happy family.
Collections of fiction in which a cat helps solve a mystery would be built using our favorite Table 3. First you have 808.83 Collections of fiction, then you have to decide between 808.831-808.838 Specific scope and types of fiction (i.e., mystery stories) and 808.839 Fiction displaying specific features (i.e., fiction about cats). The Manual note at 808.8 gives preference to specific themes and subjects (i.e., cats), but that is over-ridden by the reference at 808.839: "Class fiction of specific scope and types displaying specific features in 808.831-808.838." So we follow the instruction at 808.831-808.838 and add 872 from T3B--30872 Detective, mystery, suspense, spy, Gothic fiction in Table 3B, and get 808.83872. At this point, we follow the instructions at T3B--30872, which say that subdivisions are added for mystery fiction alone, and that you add as instructed under T3B--102-107. Here, we are told to add 08 Collections of literary texts, then notation from Table 3C. In Table 3C, we go to T3C--362 Animals, then add "the numbers following 59 in 592-599, e.g., cats T3C--3629752". You should check in the schedules that 599.752 Felis includes domestic cats (even though the interdisciplinary number for domestic cats is over in 636.8 Cats). And you get 808.83872083629752, meaning collections of detective, mystery, suspense, spy, Gothic fiction from more than two literatures with animals of the genus Felis as a subject.
So the "phantom zone" must be between 646.78 and 808.83872083629752.