Tell your readers what your subject is, what conversation you are focusing on, and what your document will tell them about it. In the following example, George Chauncey begins by announcing his topic in a straightforward manner.

The place of lesbians and gay men in American society has dramatically changed in the last half century. The change has been so profound that the harsh discrimination once faced by gay people has virtually disappeared from popular memory. That history bears repeating, since its legacy shapes today’s debate over marriage.