| Call Number | Subject |
| T | Technology |
| TA | Engineering. Civil engineering. |
| TC | Hydraulic engineering. Ocean engineering. |
| TD | Environmental engineering |
| TE | Highway engineering. Roads and pavements. |
| 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. |
| TS | Manufactures |
