What if a patron wants to find books on a certain subject?

Library of Congress Classification: Q-T

Q-T (Level 3)

Q  Science                               R   Medicine

Q: Science (General)

R: Medicine (General)

QA: Mathematics

RA: Public aspects of medicine

QB: Astronomy

RB: Pathology

QC: Physics

RC: Internal medicine

QD: Chemistry

RD: Surgery

QE: Geology

RE: Ophthalmology

QH: Natural history (General)

RF: Otorhinolaryngology

QH: Biology (General)

RG: Gynecology and obsetetrics

QK: Botany

RJ: Pediatrics

QL: Zoology

RK: Dentistry

QM: Human anatomy

RL: Dermatology

QP: Physiology

RM: Therapeutics

QR: Microbiology

RS: Pharmacy and materia medica

RT: Nursing

RV: Botanic, Thomsonian, and eclectic medicine

RX: Homeopathy

RZ: Other systems of medicine

S   Agriculture T   Technology

S: Agriculture (General)

T: Technology (General)

SB: Plant culture

TA: Engineering (General), Civil engineering

SD: Forestry

TC: Hydraulic engineering

SF: Animal culture

TD: Environmental technology, Sanitary engineering

SH: Aquaculture, Fisheries, Angling

TE: Highway engineering, Roads and pavements

SK: Hunting sports

TF: Railroad engineering and operation

TG: Bridge engineering

TH: Building construction

TJ: Mechanical engineering and machinery

TK: Electrical engineering, Electronics, Nuclear engineering

TL: Motor vehicles, Aeronautics, Astronautics

TN: Mining engineering, Metallurgy

TP: Chemical technology

TR: Photography

TS: Manufactures

TT: Handicrafts, Arts and crafts

TX: Home economics, Hospitality industry