How can I insert a subject line in a letter?

Question

I am writing a letter and I would like to insert a subject line above or below the \opening. How should I do this? I prefer not to use scrlttr2 or KOMA.

Answer 1

There's no specific command for subjects in letter style, so do something like this:

\bigskip
\textbf{Subject line}

\bigskip\noindent
First paragraph of text...

Answer 2

I know an answer has already been provided, but I would like to propose an alternative solution that I believe is more elegant. I would include the subject as the last line of the to-address, I also believe this is sometimes done intentionally so the subject is visible in windowed envelopes.

This would result in

...
\begin{letter}{Name\\Street\\City\\%
   \textbf{Subject: subject}%
}
...
\end{letter}
...

Answer 3

The answer where the subject is part of the address is not that elegant if I say so myself. Although if you place a tilde (~) in as a line, you get an empty line after the address and it looks nicer.

...
\begin{letter}{Name \\ street \\ city \\ ~ \\ subject}

....

Answer 4

I suggest using a two-line opening for this:

…
\begin{letter}{…}
  \opening{
    {\bf Subject: inquiry} \\[1cm]
    Dear Sirs,
  }
  …

which will be typeset above the text, but below the address.