For software teams practicing Agile, we recommend “Agile Excellence for Product Managers: A Guide to Creating Winning Products with Agile Development Teams” by Greg Cohen. Unlike most other Agile writings, which are very development-centric, this book takes a holistic view of how four separate constituencies (product managers, UX designers, developers, software quality assurance engineers) must work together to build a great software product.
If you don't want to read the full book you can also get a taste of how agile can be applied to early startup teams and/or hardware teams learning to add software components by reading Elaine Chen's primer on the agile development process here.
This article builds on content developed by the Martin Trust Center for MIT Entrepreneurship for MIT's Orbit Knowledgebase and is licensed under CC BY-NC-SA 4.0.