Tufte is brilliant, and this is the missing manual on report and user-interface design. Its very good at making you think differently - much like a Guru of The Week for design.
I purchased this book so that my team could use it for inspiration on new report designs (KPIs, dashboards, trend analyses etc). Our primary problem being that we work with non-math/technical people who needed very simplified reports for complex problems. Tufte's work and cutting analysis seemed a good place to start.
Don't be fazed by the fact that the examples in this book have no immediate relevance to your problem: just thumb through the book, and try to understand why the examples are good or bad. A number of patterns will start to emerge, and its these patterns that will inspire and direct you to your solutions. For example, we took the Japanese map at the beginning, combined it with the no-gridlines rule and the novel train-timetables and ended up with a simple printed report which condensed multi-dimensional information into a perspective drawing interspersed with floating blocks. So instead of churning out pages of Excel reports, we created a simple dashboard that uses colour and perspective to draw focus to the important data. If you keep an open mind, and ignore your technical limitations, you will learn a lot from this book.
However, this book will only show you design inspiration; it will does not consider how the designs can be implemented or applied, and it does not explain the art of data analysis, KPI/Scorecard design. It is very shallow in any area other than report design.
The Visual Display of Quantitative Information should be read alongside this book. For technical issues of implementing these ideas in Excel/Office, I would recommend
Balanced Scorecards and Operational Dashboards with Microsoft Excel. That said, this books ideas are best implemented in html.