Anne McCaffrey 
Get Off The Unicorn [EPUB ebook] 

From the lady who taught dragons to fly and rockets to sing…The Smallest Dragon Boy. The only thing Keevan wanted in his life was to be a dragonrider just like his father. Surely nothing could be as thrilling as soaring through the air between the powerful wings of a dragon…But Keevan was small and there were always more boys than there were dragons — someone must be disappointed. Keevan wasn’t exactly the foremost candidate but dragons have their own standards, especially the bronzes, the most jighly-prized dragons of all…This and thirteen other superb stories are collected for the first time here, in Get Off the Unicorn.