Start with the name of the person who wrote the introduction. This name should be written in the order of last name, first name, middle initial. If you do not know the entire first name or the middle initial, then just use the last name and the first initial. For example, if Jeannie B. Kinstin wrote the introduction to a source that you used, then your citation should begin: Kinstin, Jeannie B.
Follow with the name of the part being cited and a period. This can be a forward, introduction, preface or letter to the reader. If you are using Ms. Kinstin's introduction, then your citation should now read: Kinstin, Jeannie B. Introduction.
Enter the title of the book, followed by a period. It should be italicized or underlined. If your word processor does not support this type of formatting, then use an underscore symbol to indicate that the words should be underlined. For example, if the name of the book is "Netting the Biggest Whale," then your reference should read, thus far: Kinstin, Jeannie B. Introduction. _Netting the Biggest Whale_.
Add the author of the main work. The name should be in the order first name, last name and preceded by the work "by". If Henry Longtree wrote the main work, then your citation should read: Kinstin, Jeannie B. Introduction. _Netting the Biggest Whale_. By Henry Longtree.
List the name of the city where the book was published, followed by the publisher. This information can usually be found on the title page or on the inside cover. The city should be followed by a colon, and the publisher by a comma. If the book was published in Miami by Fishtail Publishing, then your citation should now read: Kinstin, Jeannie B. Introduction. _Netting the Biggest Whale_. By Henry Longtree. Miami: Fishtail Publishing,
Finish with the year of publication and the page numbers of the portion of the book cited. Each should be followed by a period. For example, if the introduction was located on pages i-xxi and the book was published in 2001, then your final version of the reference will look like this: Kinstin, Jeannie B. Introduction. _Netting the Biggest Whale_. By Henry Longtree. Miami: Fishtail Publishing, 2001. i-xxi.