The first sentence of the Foreword for New Rules exclaims "No more books by talk show hosts." Bill Maher probably should've listened to his own advice because New Rules is a huge splash in Lake Disapppointment. Sure it has its moments but overall it's a crappy effort. You can't blame people who say Mr. Maher needs to step away from book publishing and just stick to television and stand-up comedy because these are where he is most effective.
This is not to say that New Rules is unreadable. Enjoyment of the book will depend on the level of your acquaintance with Maher's body of work. If you are a fan of the man and have seen him strut his stuff on television, then New Rules will likely disappoint you. He is very good on TV that you'd expect him to be as good in book-form. Unfortunately, such is not the case. To truly experience and grasp Maher's brand of humor, you need to watch him, not read him. You need to see him smirk and giggle as he delivers his punch lines. You can't experience these if you are merely looking at words on paper.
In the case that you aren't too familiar with Maher and his work or you've never heard of him before, New Rules could be an enjoyable read. This is because of the absence of the great expectations you might carry along with you if you've been previously exposed to his work.
New Rules can be read in just one sitting. Although it has 240 pages, over 50% of these are occupied by photos and empty space. Each page usually contains two or three short paragraphs with one or two accompanying images. If you are a quick reader, you can easily make it to the last page in a span of two to three hours.
Topic-wise, New Rules is a boiling cauldron of everything. Maher has something to say about a lot of things - politics, religion, celebrity worship, stupidity, popular culture, sports, etc. - and he does it without holding anything back. He wasn't called by Tom Shales of The Washington Post as the "gutsiest, boldest, and least inhibited" of all the comic commentators out there for nothing.