The call number that is used to find a book on the shelf is based on the Library of Congress (LC) Classification system. Books are organized by subject so you can browse the shelves for books on the same topic.

The first alphabetical component of an LC call number denotes the subject of that book. Each letter represents a designated subject, then within that designation, the subject is further narrowed.

This table describes how to read a call number:

1) Books are arranged alphabetically by the initial letters in the call number ...	H451 .Z682 1998	HA126 .I90 1987	HB12 .I90 2000	HC13 .C55 1952
2) ... then numerically by the numbers after the letter or letters. These numbers are read as whole numbers - 1, 2, 3 ... 101, 102, 103 ... 1001, 1002, 1003, etc.	BF1 .J575	BF699 .D46	BF1028 .B45 1993b	BF1125 .G38 1992
3) The letters that follow the decimal point are read alphabetically.	BF699 .D46	BF699 .H5	BF699 .J6	BF699 .P7
4) The numbers that follow the the decimal point are in decimal order.	PS3569 .A462345 D45	PS3569 .A5137 F4 1984	PS3569 .A52 B58 1999	PS3569 .A5452 A44 1996
5) There may be a second letter-number combination after the decimal. These should also be read in decimal order.	PS3566 .A6948 B3 1994	PS3566 .A6948 E43 1998	PS3566 .A6948 J64 2000	PS3566 .A6948 W5 1997
6) The four numbers at the end of the record are the publication date.	BF1028 .B45 1993	BF1028 .B45 1993b	BF1125 .G38 1992	BF1125 .G38 1995