This book is just brilliant. It was actually originally written in 1978. For me, it's in the same league as "The Mythical Man-Month". Right now, I am wrestling

This book is just brilliant. It was actually originally written in 1978. For me, it's in the same league as "The Mythical Man-Month". Right now, I am wrestling with exactly the same issues: designing data structures for representing real-world entities, discovering the roles they play (in a financial decision in my case), gathering data about the entities (depending on their roles), confirming the relationships between them, and validating attributes about them, based on primary data with differing degrees of reliability. I've been through various iterations, painfully getting better at representing "what is true and what don't we know yet". Reading "Data and Reality" just now was like a distillation of my endeavour, all in one place. Plus lots of things I haven't properly considered yet. I can see why many people find it dull: if you haven't struggled with representing these distinctions yourself, it can well sounds like pointless nitpicking and overcomplicating straightforward situations. So a big thank you to the original poster, Tomte.