Definitions of in a nutshell on the Web:

• summed up briefly; "gave the facts in a nutshell"; "just tell me the story in a nutshell"; "explained the situation in a nutshell"
  wordnetweb.princeton.edu/perl/webwn

• Kevin Scott Collier (born 1957 in Muskegon, Michigan) is a comics writer and illustrator, children's book author and illustrator, and columnist for several online and print magazines. Collier graduated from Mona Shores High School in 1975, and briefly attended Muskegon Community College. ...
  en.wikipedia.org/wiki/In_A_Nutshell

• In a Nutshell is the second album by Swedish singer-songwriter Pelle Carlberg.
  en.wikipedia.org/wiki/In_a_Nutshell_(album)

• In summary; briefly or simply
  en.wiktionary.org/wiki/in_a_nutshell