Hello everybody.

I am applying for a postdoc position in the US.
The short-postdoc opportunity comes with a call, and I don't know who is the responsible reviewing my application: so I am tempted to start with a "Dear Sir/Madame". Or should I address to someone that is working inside the lab (two co-directors) anyway, even if I don't know who is going to judge my application?

Now, two questions for you:

- what do you think is the correct length?
(Right now I have written 650 words, describing the topics covered within my thesis, my aspiration and why the postdoc would benefit me, my interests in the postdoc, and how my experience would turn useful to the hosting institution and postdoc project.)

- any advice on what's particularly important to write there?

Write it to a specific person.

Cover letters should be one to two pages, so 650 words sounds about right.

There's a formula for these things, which is slightly different to the UK, so look online to find out what this is. Try sites like http://theprofessorisin.com/ and the forum on Chronicle.com is very good. US CVs are quite different as well, so google for examples.