The third column ("Book") refers to the Volume where the mortgage details can be found (First = Volume I; Second = Volume II).
The second column ("Page") is the number of the page in that volume with the mortgage details.
The first column is the names of the mortgager and mortgagee.
These mortgages, as recorded by the City Clerk, are chattel mortgages of personal property offered as collateral to a lender. They are not real estate mortgages.