Each is 6x7-5/8" soft cover with 24 pages published by Stellar Publishing Corp. New York ©1932 Gernsback Publications Inc. Numbers, titles, and authors include: #13 The Men From the Meteor by Pansy E. Black, #14 The Flight of the Aerofix by Maurice Renard, #15 The Invading Asteroid by Manly Wade Wellman, #16 The Immortals of Mercury by Clark Ashton Smith, #17 The Spectre Bullet by Thomas Mack and the Avenging Note by Alfred Sprissler, and #18 The Ship From Nowhere by Sidney Patzer and the Moon Mirage by Raymond Gallun. Booklets have no illustrations except for small Gernsback logo on front cover of each. We believe that these stories were not quite good enough for publication in Gernsback pulps and thus were issued in this special series which likely had low distribution. None have cover price and were likely available by subscription only. Trace of lt. cover dust soil here and there, #18 has a few faint moisture marks on back cover but overall group is VF/Exc. Scarce.