Damn goverment trying to destroy Dewy's legacy.
Sounds like a pretty vague system, that might actually make it harder to find what you are looking for rather than easier.
Most Academic Libraries along with law, health, and special libraries use LCC. Dewey is used primarily in school and public libraries. LCC is designed to give more detailed description of location (the break down of the call number) of the material because DDC does not include all potential subjects. To do so would require and infinite number of classes.
Main Classes of LCC
A= General work
B= Philosophy
C= Auxiliary Sciences of history
D= Old world history
etc....
H is the social sciences.
Examples of Expanding to subdivision.
HV6085 = general works on the language of criminals
HV6089= Prison psychology
HV6093= general works on intellectual and aesthetic characteristics of criminals
HV6097= Prison literature, wall inscriptions
It expands futher into decimal points more numbers.
.
HV5831 .M46 T734 2003
HV5831.17 K27 E58 1998
HV6178.235 H48 Q69 1991
I made these up don't try to actually look for them.
I don't fully understand if all, we only touch lightly upon it in TS class. I don't take cataloging until the summer.