What is cover letter?

[arcticmaple]

Hi,
    I'm applying to FSW through a consultant and I've submitted all my documents to my consultant almost one month ago. I dont understand why my consultant is taking too much time for preparing cover letter? do anyone know what is cover letter all about and how important it is while filing documents. I kept asking my status from my consultant and his reply always would be preparing cover letter. This has been going on for nearly 15-days. I'm scared whether i'll miss  the cap. Can anybody let me know what is cover letter all about and its importance.

Thanks in advance.

[shibuya]

Before u send a biodata across for an job  interview  u send along with it a brief cover letter . This is a similar one u send along with ur full docs highlighting any major changes etc.