You can definately define styles without simply listing artists. There are several good books on understanding jazz styles. In fact listing artists is not really very useful. Miles for example began in bop, helped create cool jazz (birth of cool), recorded one of the first real hard bop ( walkin) albums, had the most significant contribution to modal jazz (kind of blue), mastered post bop ( miles smiles), and led the vangaurd of fusion. The very best place to start in my opinion is to read 'Louis Armstrongs New Orleans' which came out recently. For anyone interested in the genesis of American popular music , styles ,influences ,and a whos who from Jelly Roll Morton to Robert Johnson read the book. It helped me see why the blues ran so deep in Armstong ,Bird,and Young but not Dizzy or Hawk . Just my opinions as always. - Jim