First off, don't think that this 2-volume set will teach you to read Chinese by itself; it's designed as a companion to his "Beginning Chinese". Each of the 48 lessons is matched to a lesson in his "Beginning Chinese"; for example, before you study Lesson 10 in Beginning Chinese Reader, you need to have learned the grammar in Lesson 8 of "Beginning Chinese".
The author stresses a couple of key points: Learning characters has to come AFTER the sound system and after at least some grammar has been introduced. And secondly, the number of characters you know is not nearly as important as the number of character combinations that you've learned, and the amount of practice that you've had with the characters.
Each lesson introduces 10 new characters, and 20 to 40 character combinations built up from the new characters and characters previously learned. All the new characters are used in "Illustrative Sentences", which are translated into English at the end of the chapter. The bulk of each lesson consists of readings, both in dialogue form and expository prose.
By the end of the 2 books, you will have learned app. 400 characters, and about 1,200 character compounds. But these are the most frequently utilized 400 characters; according to a study cited, these 400 characters account for 73% of all the characters found in books, periodicals, and other sources.
The book uses traditional characters, although in the back of volume 2, the authors gives the simplified versions, and a small bit of practice using these. Like the companion "Beginning Chinese", the topics are somewhat dated ... you constantly read about so-and-so not having enough money to send his children to college. But overall, if you're seriously interested in the Chinese language, and you're willing to invest the time and energy to do it right, the DeFrancis series is the surest way to get a sound foundation in Chinese.