The 2007 book is worth getting for its coverage of Binaltech and Alternators, and in depth looks at the first movie toys (although 2009 vol 2 is more comprehensive on the movie figs and there's another book about Binaltech in much more detail).

There's also the Machinerobo Wedge book, which is by the same publishers and is basically the Machine Man equivalent of Generations. The difference between the Japanese series and the Western version is vast, but if you like looking at pictures of toy robots that convert into vehicles its quite interesting.