社交、亲友这间的相互介绍，常用介绍信联系。收信人从介绍信中可以了解到来者是什么人，要办什么事，有什么具体要求等。
写这类书要注意慎重、谦恭。在信封左下角常写有To introduce ……或Introducing……,信封一般不封。
1. 介绍中学同学 Introducing a middle school classmate
Dear [Mr. Chang].
The bearer, [Ms Huan], is a classmate of mine at middle school, who has recently been assigned to work in your city. [She] is well educated, having good habits and agreeable manners. Any assistance you may give [her] concerning [her] life will be esteemed as a great favor for me.
Yours truly,
亲爱的[常先生]：
持信人[黄女士]是我的一位中学同学，最近[她]被派往你市工作。[她]受过良好的教育，没有不良的习惯，举止端庄。您对[她]生活上的任何帮助，将使我感同身受。
2. 介绍本人 Self-introduction
Dear [Sirs],
From your advertisement in [yesterday’s USA Today] I find that you are wanting a [Chinese teacher] in your college. I beg leave to take the liberty of offering myself for the position.
Born in [Beijing] in [1970], I am a graduate of [Beijing University], and therefore have a good knowledge both in Chinese and English.
Should my application be regarded favorably, I shall endeavor to justify the confidence you may repose in me.
Faithfully yours,
亲爱的[先生们]：
[昨天《今日美国报》]载你院需[汉语教员]。我申请任此职务。
我[1970年]出生于[北京]，毕业于[北京大学]，汉语和英语均有所长。
如蒙录用，自当竭诚服务，以答雅意。
此致
敬礼！
3. 去具体单位的介绍信 Letter of introduction with a known unit
China travel Service
[April 15, 1993]
Bureau of Travel and Tourism
Administration
Gentleman in Charge,
The bearer of this letter is [Mr. Zhang Wen], who is entrusted with task of making the necessary arrangements with you for our going to your Bureau to attend the report on [Current affairs].
Please favor [him] with an interview.
兹介绍[张文先生]前往你处联系有关我们去你局听[形势报告]的事宜，请予接洽为荷。
此致
旅行游览事业局
中国旅行社
4. 去不明具体单位的介绍信 Letter of introduction without a know unit
[Beijing] University
[Oct. 9. 2004]
To whom it may concern,