Bidrag Till K?nnedom Om Sveriges Salmonider by Hjalmar Widegren, originally published in 1863, offers a detailed exploration of Swedish salmonid fish species. This historical scientific work provides valuable insights into the understanding of fish populations in Sweden during the mid-19th century. Researchers and enthusiasts of ichthyology will appreciate the detailed observations and findings presented in this comprehensive study. The book stands as a significant contribution to the field of zoology and natural history, documenting the characteristics and habitats of various salmonid species. This edition makes a foundational work accessible to a new generation of scientists and historians.