The Catch Trap by Marion Zimmer Bradley. A non-sf/non-fantasy not-quite-"straight" historical of hers. Available
DRM-free worldwide @ Fictionwise and discountable with the weekend coupons posted in the Deals forum.
It's a thinly veiled history of aerialist performers combined with a 50s-era coming-of-age of young gay men in a repressive and punitive society (with tense family dynamics due to closeting fallout) story. Quite good, IMHO, and lots of stuff about the mechanics and dynamics and development of trapeze artistry and the circus ranging from tiny travelling carnival shows to "big-ring" televised acts, but somewhat depressing due to period-accurate portrayals of prejudice against gay men (and women in general) and some may find the depiction of underaged teen sexuality in one of the protagonists disturbing due to the
situation with MZB's late second husband, who IIRC is thanked in the credits of the book for providing "insight" or whatnot.
Recommended with caveats due to the last, if you know what you're getting into and think you want to try it anyway. I did quite like much of this book and if you're really into how-it-works-and-has-changed-over-time circus/performance stuff, there's plenty woven throughout the story to keep you fascinated if you don't care for the main plotline.