A parts book or parts catalogue is a book published by manufacturers which contains the part number

Part number

A part number is an identifier of a particular part design used in a particular industry. Its purpose is to simplify referencing to that part...

s and other relevant data for their products or parts thereof.

Parts books were often also issued as microfiche

Microform

Microforms are any forms, either films or paper, containing microreproductions of documents for transmission, storage, reading, and printing. Microform images are commonly reduced to about one twenty-fifth of the original document size...

, though this has fallen out of favour. Now, many manufacturers offer this information digitally in an electronic parts catalogue (EPC). This can be locally installed software, or a centrally hosted web application

Web application

A web application is an application that is accessed over a network such as the Internet or an intranet. The term may also mean a computer software application that is coded in a browser-supported language and reliant on a common web browser to render the application executable.Web applications are...

. Usually, an EPC enables the user to virtually disassemble the product into its components to identify the required part(s).

In the automotive industry

Automotive industry

The automotive industry designs, develops, manufactures, markets, and sells motor vehicles, and is one of the world's most important economic sectors by revenue....

, EPC's are also able to access specific vehicle information, usually through an online look-up of the Vehicle Identification Number

Vehicle identification number

A Vehicle Identification Number, commonly abbreviated to VIN, is a unique serial number used by the automotive industry to identify individual motor vehicles. VINs were first used in 1954...

. This will identify specific models, allowing the user to correctly identify the required part and its relevant part number.