Oi, I wish they made Excel and Word function the same way. Yes, in Excel 4 through 2003 (and maybe 2007), all the open documents are contained within a single Excel window. Just the opposite of Word.

Your best hopes for window organization are Restore and the Window menu.

Restore is one of the three buttons in the upper left of every program and document window. There's the minus button (minimize), the maximize/restore button, and the X button (close). Clicking Restore will reduce the document window to something smaller and sizeable within the Excel workspace window. With a few docs open, you could move them around and overlap them.

Also, the Window menu will help you arrange multiple documents without overlap. Window > Arrange > Horizontal lines up windows in stripes across the Excel workspace. But how do you easily get them in the right order (top to bottom, left to right)? Here's a trick I learned back in Office 4.3: Click each window in reverse order that you want them to appear. The last clicked window will appear on the top/left, first appears on the bottom/right, and others appear according to that backward sequence. If you want Book 1, Book 2, and Book 3 to appear in that order from top to bottom, click Book 3, then 2, then 1, then Window > Arrange > Horizontal.

Oh, and don't Alt-F4 on an Excel document or it will begin to close all of them. Ctrl-F4 closes a single Excel document (and closes a single Word document).