Seven books for designing the whole thing a person is trying to do, rather than the screen in front of them.
Service design covers the parts of an experience that no single team owns, including the letter that arrives after the form is submitted and the phone call that follows the letter. These books give you the methods for mapping that whole, the principles for judging whether it works, and the research practices that keep it grounded in what people are actually trying to accomplish. The first is a working handbook, and the rest go deeper on particular parts of it.
The handbook of activities, with step by step instructions for journey mapping, service blueprinting, stakeholder mapping and desktop walkthroughs. Later chapters deal with running a project in an organisation where nobody has done one before.
Downe's fifteen principles for a service that works, drawn from leading design at the UK Government Digital Service. Short and illustrated, which makes it the one to hand to a stakeholder who will not read a handbook.
Young's method produces a picture of what people are trying to accomplish, aligned against what your organisation currently offers, and the gaps in that alignment are exactly where a service leaves someone stranded. Long, and the analysis chapters are the reason to read it.
The method reference for the research and evaluation work a service project generates, indexed so you can match a method to the question rather than reaching for interviews every time.
Service problems are usually reasoning problems, and Young's listening sessions surface how someone thinks rather than what they say about your service. Short, and best read before a round of interviews rather than after.
Services come apart on language more often than on layout, and Covert's book is mostly about language. Useful when the same thing carries four names across four departments.
The fourth edition covers cross channel and device independent structures, which is the problem a service faces as soon as it spans a website, a call centre and a letter. The governance material matters here, because a structure spread across departments decays faster than one owned by a single team.