When I originally started watching Ghost in the Shell: Stand Alone Complex on Adult Swim, I was rather pleasantly surprised to find a tightly-plotted political drama. GitS:SAC is very much not the average anime, so I was pleased to find out that the tie-ins marketed around it were a bit left of center as well.
Taking up the tradition started by Ghost in the Shell 2: Innocence: After The Long Goodbye, The Lost Memory is a prose novel that takes the reader a little bit deeper into the GitS world. This novel focuses on suicide bomber teenagers and their possible threat to a world peace leader. (The theme of teenagers as a group being such a cause of alarm to the greater populace seems to be paralleled from the film Battle Royal. Being from a Western country, it is interesting to take note of the small but telling and important differences in philosophy and social tension.)
Unlike After The Long Goodbye, The Lost Memory is sheer adventure fun. It is set during the series' first season and generally does a great job of building on the show's established universe. The characters are spot-on (helped, I'm sure, but the author being one of the series writers), and the prose is above average for other media tie-ins that I've encountered. Basically, it's worth the $9 to revisit the GitS:SAC universe.
I very much plan on buying the other books and hope there are quite a few of them. The series is addictive and intense, and if the rest of the books are on par or better than this one, I shall be a happy, happy girl.