There are several documents that are descrbed as Bodies of Knowledge that business analysts should be aware of.
In alphabetical order
BABOK - Business Analysts Body of Knowledge, by the IIBA
NPDBOK - New Product Developmet Body of Knowledge, by NPD Solutions
SWEBOK - Software Engineer's Body of Knowledge, by IEEE Computer Society
G2SEBoK - Guide to the Systems Engineering Body of Knowledge, by INCOSE
There is also several versions of a Project Management BOK, the main one being published by PMI.