This book devotes too much to VB, not enough to Excel specific functions. Or the Excel part is way out of proportion. Many chapters may be removed to make it concise: chapter 1, 5, 6, 25 - 28, and any references to Lotus1-2-3, Quattro Pro, XLM macro. Replace Part VII by how to interface to 300+ Excel functions.

On software reuse, one should always use those tools that are available (and tested). The author seems to favor duplicating Excel functions in VB. On page 293, he wrote on sorting an array, " workaround is to transfer your array to a worksheet range, sort it using Excel's commands, and then return the result to your array. But if speed is essential, it's better to write a sorting routine in VBA."
First, I doubt about the speed claim. Second, even if the speed gain were true, taking the time to write a new (and reliable) sorting routine is hardly justified in practice. Third, what about the other Excel functions you have to use tomorrow ?