This is a book review of The Cosmos: Astronomy in the New Millennium by Jay M. Pasachoff & Alex Filippenko. A truly massive tome, this is an undergraduate textbook intended as "a descriptive presentation of modern astronomy for liberal-arts students", though it should appeal as well to those who enjoy popular-astronomy books. Essentially all of astronomy is covered in the twenty chapters; roughly a quarter each is assigned to general background (physics, history of astronomy, instrumentation), the Solar System, stellar astronomy and the Milky Way, and extragalactic astronomy and cosmology. The material is correct, up-to-date, and well presented (with very few typos); the book is obviously a labour of love. (The book would be impressive enough if the authors were only teachers; Filippenko is also one of the most highly cited astronomers.) The authors state that it is a `how and why', rather than a `what and where' book. In other words, although not intended for science majors, and though maths are kept to a minimum, the presentation is not just qualitative, but an attempt (successful, but of course at the intended level) is made to explain the reasons behind the phenomena. Neither is it a `who and when' book, though some basic history of astronomy is of course included. Eight appendices, including photos of all Messier objects, are a nice addition. Six-and-one-half pages of suggestions for further reading (again in small print), grouped by topic, some with comments, will probably satisfy the curiosity of most readers. The front- and end papers (inside cover and facing page) contain eight sky charts, one for each season with views to the north and south, as seen from North American latitudes. (My only criticism is that the book sometimes assumes a North American readership, though to be fair courses for which the book is intended are much more common there than elsewhere.) The literally thousands of high-resolution colour images in this book are presumably made possible by economies of scale; indeed, the price would be reasonable for a book of this size with no pictures at all.