I'm a budding inventor who wanted to protection for a children's toy I invented recently. Using this book, I filed a patent application in about 15 hours.
To understand the value of this book, you need to understand that there are two types of patent applications.
The first is a Provisional Patent Application (PPA) which is an informal patent application that simply establishes a filing date and allows you to legally use "patent pending" for 1 year, when sharing your invention with others and testing its marketability. The second is a Regular Patent Application (RPA). This is a formal application at which the Patent Office looks closely and can result in patent protection for the next 20 years if it's granted. The PPA costs $100 for most, and the RPA costs thousands upon thousands.
This book helps you file a Provisional Patent Application (PPA).
I found it to be very clear, and told me what I had to do. It assumes you know nothing. I found it's example illustrations very helpful as I made up drawings, and particularly helpful was how to navigate the US Patent and Trademark Office site to download and fill out applications. It also gave some good tips for patent searching. The sample PPA, a doll that has "light-up" tears, gave me a good idea how to write the PPA.
I did find, however, that the author constantly uses phrases like "For more information, see my book "Patent it Yourself" which I found a little frustrating. I ended up finding a copy of Patent It Yourself in the library to get some of my questions answered.
Also, some foreign offices require information that is not explained in Patent Pending in 24 Hours (at least one "claim"), so I had to use Patent It Yourself to get this information, and include it in my PPA, so in this respect, Patent Pending in 24 Hours is not complete if you want international protection eventually.
I recommend that you get both Patent It Yourself and Patent Pending in 24 hours if you want all your questions answered. They both contain information not found in the other.