Blue and Gray is an strategy board game for two players invented by Henry Busch and Arthur Jaeger in 1903.
 They obtained a patent for the game, but may never have published it.
 Blue and Gray was featured in the book "A Gamut of Games" (1969) by Sid Sackson.
 It was also featured in "The Book of Classic Board Games" (1991) by Klutz Press under the name Cats and Dogs.
 In this book, the game was ranked among the top 15 board games of all time, including checkers, backgammon, Go, and mancala.
 The game is also known as Wild West, Thumps Game, and Captain and Soldiers.
 The name Blue and Gray "refers to the uniforms of the South and the North in the Civil War and in the original game the playing pieces of the contestants were of those colors."
Mag Blast is a spaceship-themed strategy card game, produced by gaming company Fantasy Flight Games.
 The first edition was set in the universe of "Twilight Imperium", a board game made by the same company.
 The game is playable for 2-8 players, and is described as "a game of screaming space battles"
Shattered Empire is the first expansion to the board game "Twilight Imperium", both of which were designed and published by gaming company Fantasy Flight Games.
 It was released in December 2006.
Shards of the Throne is the second expansion to the board game Twilight Imperium, both of which were designed and published by gaming company Fantasy Flight Games.
 It was released in May 2011.
Crossings is a two-player abstract strategy board game invented by Robert Abbott.
 The rules were published in Sid Sackson's "A Gamut of Games".
 Crossings was the precursor to Epaminondas, which uses a larger board and expanded rules.
A Gamut of Games is an innovative book of games written by Sid Sackson and first published in 1969.
 It contains rules for a large number of paper and pencil, card, and board games.
 Many of the games in the book had never before been published.
 It is considered by many to be an essential text for anyone interested in abstract strategy games, and a number of the rules were later expanded into full-fledged published board games.
Death Stacks is an abstract strategy board game for two players invented by Stephen Euin Cobb.
 "Death Stacks" can be classified as a variant of the game "Focus" by Sid Sackson, published in "A Gamut of Games".
Three Musketeers is an abstract strategy board game by Haar Hoolim.
 It was published in Sid Sackson's "A Gamut of Games."
 The game is notable in that, like the traditional Fox and geese, it uses the principle of "unequal forces"; the two players neither use the same types of pieces nor the same rules, and their victory conditions are different.
Focus is an abstract strategy board game, designed by Sid Sackson and first published in 1964 by Kosmos.
 The game has been re-published many times since, sometimes under the titles "Domination" or "Dominio".
 "Focus" won the 1981 Spiel des Jahres and Essen Feather awards.
 The game appears in Sackson's "A Gamut of Games" in the section "New Battles on an Old Battlefield".
Twilight Imperium is a strategy board game produced by Fantasy Flight Games.
 It was designed by Christian T. Petersen and was first released in 1998.
 The game is in its third edition (2005), which has large changes over previous editions.
 This edition also has two expansions – "Shattered Empire" released in 2006, and "Shards of the Throne" released in 2011.
 It is known for the length of its gameplay (typically greater than 6 hours), and its in-depth strategy (including military, political, technological and trade).

Question: Which strategy board game, Twilight Imperium or Focus, appears in Sackson's "A Gamut of Games"?
Answer: Focus