This story first appeared in the Feb. 15 issue of The Hollywood Reporter magazine.

Katy Perry's "Teenage Dream," Taylor Swift's "I Knew You Were Trouble," Bruno Mars' "Locked Out of Heaven" -- the secret ingredient in these pop hits is behind the scenes: the songwriters, producers, A&R executives and multihyphenate artists who help create those irresistible hooks.

Their services don't come cheap -- from $30,000 to $100,000 per song for the top-tier masters of the craft, often with points as incentives -- but the residuals of a Top 10 hit can last a lifetime. In recent years, however, it's become common to see as many as a dozen names credited on a single tune, which means the slices of the publishing pie are getting smaller. Still, there's plenty left to nosh on, as these 35 in-demand hitmakers prove.

Selection Criteria: For THR’s Hitmakers list, editors based their selections on the following: single and album sales, chart position achieved, current Grammy nominations and years in the business.

Written by Michele Amabile Angermiller, Steve Baltin, Fred Bronson, Rebecca Ford, Sharifa Godfrey, Nisha Gopalan, Shirley Halperin, Sophie Schillaci, Bud Scoppa, Colin Stutz, Georg Szalai, Jeff Weiss, Chris Willman, Stacey Wilson and Emily Zemler.