Library of Congress call numbers are arranged alphabetically and numerically. Read call numbers from left to right and from top to bottom.
Letters in the first line of the call number are alphabetical:
| H 45 .E37 1984 |
HA 155 .A5 1944 |
HB 21 .A33 1982 |
HC 13 .S47 1990 |
Numbers in the second line of the call number are in numerical order:
| B 53 .D476 1990 |
B 785 .L44 M67 1991 |
B 1201 .B44 W64 1997 |
B 1246 .R66 1986 |
Letters in the third line are alphabetical:
| KF 240 .B265 1981 |
KF 240 .C538 1989 |
KF 240 .S795 1995 |
KF 240 .T38 1989 |
Numbers in the third line of the call number are in decimal order. It is important to remember that there is an “invisible” decimal point between the letter and the number:
| L 901 .C33 |
L 901 .C34 1971 |
L 901 .C343 1976 |
L 901 .C37 1996 |
There may be a fourth line of letters and numbers. These will also be in alphabetical and decimal number order.
The last line of a call number may be a year. This indicates the publication date.