copy / paste to another workbook

[Hein]

Hi all,

I have to gather a LOT of information from different files, into 1. To do so I want to automate this.

1. I will make a new, target file
2. I want to have a file with the macro in it
3. i want to open a (various) number of files to copy the info from

Now for my questions:
* How can I determine which other files are open (apart from the new and macro file)?
* How can I access each individual file, copy the information, paste it in the target file and close the "copy-file" after this
* Within the previous *): how can I determine how many worksheets there are in each file and do the copying sheets by sheet?

Who knows what to do?

Thanks in advance
Hein