The free downloaded contents pages are in pdf format (about 100KB each).
Tip. If you RIGHT click any download and Save Target As... you will keep a copy on your own computer which you can read at leisure. It also usually works as an alternative when Acrobat fails to open the file directly with a LEFT click.
Contents Pages of Individual Chapters
Ch. 5.0 Lycaenidae Introduction (contains essential introductory material for chapters 5.1 to 5.22), 13 pages, download.