It's rare to see an author that not only covers a language breadth but also isn't afraid to reach depths in practical applications. This book is tailored towards a computer or data scientist, although the layperson with a good foundation in discrete math, calculus and statistics will feel comfortable. The first third covers the language itself, slowly introducing language semantics and common patterns before sliding into statistical analysis such as p values, linear regression, etc. If I had to nitpick, from an engineering perspective I would have enjoyed digging into the S4 structure. My page tabs are on 48, 84, 97, 130, 171, 176, 207, 227, 242, 251, 274, 278, 298, 326, 369, 378, 387, 391, 405, 460 & 463.