No problem. This site has it available right now. https://ebookclass.com/product/the-architects-handbook-of-professional-practice-15th-edition-ebook-pdf/
Lydia, I would say that all of parts 3 & 4, plus chapter 9 would be similar recommended content to that of AHPP 15. Having had access to both, I would say 15 is far more clear and up to date. ...