Staff Engineer: Leadership beyond the management track (English Edition) https://amzn.eu/d/d3CwEuc
#bookshelf . Staff+ is relatively new grade but quite old concept . Leaders without direct reports that do impact without formal titles with informal empathy and experience based approach . Every organization has different view on this position but for me it is always about empowering and enabling others . It is more about concepts , principles and ideas.
Book is quite good intro to taxonomy of staff+