Why are variables missing from the code book?

Why are variables missing from the code book? For example, PUMA, INCTOT and FINCTOT are listed at the beginning of the code book, but they are not defined. I looked through the entire code book, but they are missing from the code book altogether. These variables are include in the data set, but I need to know how they are defined in order to recode them.

The basic codebooks that accompany IPUMS extracts primarily display value labels. The variables that do not have value labels are not listed in the basic codebook. The variables INCTOT and FINCTOT are both dollar figures so they do not have value labels. PUMA codes represent geographic areas, but most PUMAs are not easily described using words, which is why the Codes section of the PUMA description includes links to maps and boundary files. The best source for information on how a variable is defined is the variable’s description page, which includes links to codes, comparability, and question text. The DDI codebook also gives more descriptive information than the basic codebook if you prefer a single downloadable document.

I hope this helps.