Totalling values from multipile files

All files in a single folder named yyyy, each file named mm-dd-yy. Each file was created from the same master template, just different data from day to day. Each file has a summary sheet that contains the values that need to be totaled in another file. This new file would hopefully update (auto or manual) each time a new file is added to the yyyy folder. New file can be located in the same folder or other wise. I am pulling around ten number from each mm-dd-yy file, and we are only open for buisness on weekends, so just over a hundred mm-dd-yy files per yyyy folder.

If from scratch I would probably have done this with a data base, however the original files were set up by another and been ran for a few years now. My task to do some market analysis on the data and any help to this function would be greatly appreciated.

I guess I should add an actuall question. I have no problem setting up the basic file, I just have not been able to figure out how to link to all files in a folder?

suppose the summary cell of each workbook is A1000
And on your master file, A1 is a date of the weekend
Use the following formula to get the location of the A1 of the file of a date

=CONCATENATE("sglife='C:\",TEXT(A1,"yyyy"),"\[",TEXT(A1,"mm-dd-yy"),".xls]Sheet1'!$A$1000")

You can copy the formula down, and get the location of differennt workbooks.
Then copy and paste special value

Then use replace to replace "sglife" with Empty