Well, if you've read anything at all that is skeptical of the official account of what happened on September 11, 2001, it is extremely likely that one of the primary sources for what you read is Paul Thompson's "Timeline." David Ray Griffin draws on it extensively, and so does pretty much everybody else. This is just indispensable raw source material. I find it more useful as a reference book, i.e., to go back in and check facts pertaining to a particular aspect of 9/11, than as the sort of book you sit down and read from front to back -- although it could certainly be read that way. If you're new to the topic, I'm not sure I'd recommend this one as the place to start. It succeeds spectacularly in its aim, to lay out the rich tapestry of the various contradictory claims and facts and let them speak for themselves, but I imagine it would be somewhat harder to assimilate for a beginner than something with more of a narrative -- more of an "argument."
Thompson deliberately shies away from suggesting "inside job" or indeed from providing much speculation about answers at all. His value is in raising the questions, pointing out the screaming inconsistencies, contradictions, incompatibilities, hot loose ends -- the things that absolutely must be explained if we are to consider that we know what happened, never mind why. And many of these questions -- most of them -- have not been answered. They have been, in all the official channels, ignored. These questions are not going away, they're too important and too glaring. If enough people become curious about them and demand answers, who knows, perhaps we could get some. Stranger things have happened.
As Donald Rumsfeld once said, there's things you know you know, things you know you don't know, and things you don't know you don't know. Make the effort to know what you don't know. Subject what you "know" to critical scrutiny. If you have any interest in 9/11 at all, even -- or especially -- if you think the "9/11 Truth" movement deserves nothing but derision -- then you owe it to yourself, and I daresay to others, to ensure that your opinion is informed. This book will help.