This book started life as a manual for the SuperTree decision analysis software package. The 3rd edition has been rewritten to be software-neutral and now incorporates the dialogue decision process (DDP) and the concepts of decision quality.
Between this and Making Hard Decisions by Robert Clemen, DAftP is the more practical, and hence better, book for the ordinary professional working with a decision analyst, or as a first text for a trainee decision analyst wanting to learn about decision diagrams and decision trees, and how these tools should be used in real-world consulting engagements. Mathematical theory is nicely relegated to the "Advanced Topics" section and well written for those with a non-advanced mathematical education.
I would have liked at least some mention of Monte Carlo simulation as an alternative to decision trees, but then it is only in the last year or so (DAftP was last updated in 2001) that Monte Carlo simulation has become a realistic alternative to simple decision tree analysis, largely abetted by the development by Sam Savage of the DIST standard for encoding probability distributions.