Research on strigolactones （SLs）, originating from isolation and identification of germination stimulants for seeds of root parasitic weeds, has led to scientific findings of immense basic and applied importance.　The term, strigolactones, was first coined in 1995 by the late Larry Butler to define chemicals analogous to strigol in structure and active as Striga germination stimulants.　Since the discovery of the novel physiological roles of SLs in hyphal branching in arbuscular mycorrhizal fungi in 2005 and in shoot branching in planta in 2008, an avalanche of articles, reflecting the outstanding importance of these molecules, appeared in eminent scientific journals.　With accumulation of our knowledge on SLs, the original definition of the term, based on the structure and the biological activity, is becoming difficult to encompass this class of natural products due to emerging structural diversity and physiological functions.　The 1^st International Congress on Strigolactones was timely held in March, 2014, to exchange ideas and knowledge on SLs and to increase the solidarity and collaboration within the SL community.　On the occasion, this special issue was undertaken to review recent progresses on SL research with emphasis on biosynthesis, perception and signaling.　The articles contributed by scientists, who have led the progresses of SLs research, will, for sure, be of help to readers to understand a wide range of aspects of SLs, including chemistry, biochemistry and physiology, and enable design and conductance of attractive research to further our understandings and knowledge on these fascinating apocarotenoids.