The Encyclopedia of Levitations & Suspensions by Sharpe available through Hades Publishing in Canada.
Though it is a bit antiquated it will give you a very solid foundation as to the standards in the industry and how they work. Bear in mind that most of this information has evolved but remains the core to how the more modern variations work as well.
You will also learn the difference between a Levitation vs. a Suspension... something few ever realize unless they get vested in grand illusions; in general terms, a "Levitation" entails the total and complete absence of any kind of physical connection such as a chair, broom, pole,etc. There are a couple of confusing exceptions to this rule, such as the Super X or Harbin styled "Suspensions" which do in fact seem to be more of a full levitation but they are exceptions to the basic rule.
There are a handful of Specialty Books that deal specifically with certain floating effects such as Stan Allan's Broom Suspension book and the new Asrah Levitation booklet. Then again, there are the troves of effects systems penned by Paul Osborne and others over the years that will give you some interesting twists on the older ideas; I highly recommend getting all of Paul's books as well as those by other noted illusion designers if you really want to become familiar with the whole genre.
Best of luck!
