The basic file you create in Excel 2008 for Mac is a workbook, saved in the Excel Workbook (.xlsx) file format. If your workbook content warrants it, you can save a workbook in a binary file format (to aid compatibility with previous versions) or macro-enabled file format (to enable macros within the workbook). These files are also referred to as workbooks. In this chapter, we examine simple workbooks in which you store, manage, calculate, and present simple data. (Don’t worry—we’re saving the hard bits for later chapters.)

One thing that is simpler in Excel than in Word is that you can create only one type of workbook by clicking the New button—a blank workbook. You don’t need to choose a specific type of workbook or worry about which type of workbook will be created.

Regardless of the type of workbook you end up with, every workbook starts out in the simple Workbook format. When you save the workbook, you can choose a different format. (If your workbook contains programmatic content, Excel might automatically select a binary or macro-enabled format in the Save As dialog box.)

If the file format you choose doesn’t support a type of content contained in the workbook, Excel warns you. For example, if you use fancy formatting in your workbook and try to save it in the Excel 97–2004 Workbook (.xls) format, Excel displays a cautionary message that the content might not be available in the new format.

Excel warns you if the file you’re saving contains elements that aren’t compatible with the selected file type.