The Treasury of Scripture Knowledge (or TSK, or simply "Treasury") is a verse cross-reference work which has been used for many years. No one knows who created the reference work. It is sometimes mistakenly credited to RA Torrey, however in one of the printed copies of the book, he has a foreward indicating that he had encountered it himself about 20 years earlier. Treasury is in the public domain.
Treasury is organized by Bible verse, and by KJV phrase within each verse and lists the verses elsewhere in the Bible that are related to that verse and phrase. It contains over 360,000 cross-references. erasmus uses this information to automatically provide a list of cross-reference verses for any verse you are reading. Therefore, you rarely will need to directly consult Treasury. However, if you want to focus on a specific phrase, opening the Treasury to the desired verse may give you better results.
Treasury is not included in the 128 Mb Edition of erasmus due to size constraints.