It's also helpful to look at book reviews too. If the book is favorably viewed by some scientific journal or other experts in the particular field your book covers, then it is probably legitimate.
The way I do it, I usually check the author, and then go to Amazon.com and Barnes&Noble's for book reviews because they list most of the people and experts that reviewed it.
As for date of publication, I think that depends on what field the book covers. In my field of interest (military, theoretical-physics, astronomy), most books more than 5 years old are already outdated. Given the title of the book you are reading, it probably should still be alright, though you should look for newer stuff given that it deals with future scenarios.
