This is one of the best books on thermodynamics I have encountered. What can often come across as a rather boring subject is helped by the lively tone of the book, along with frequent biographies of historical figures.
The book is nicely structured, starting off with the basics, moving on to the laws of thermodynamics and statistical mechanics, and including additional topics often not covered in other thermodynamics textbooks, such as stars and black holes. There are also helpful appendices with the main mathematical techniques explained, though you really do need to have a grasp of differentiation and integration before studying this book.
Overall then, and excellent textbook, well worth a read.