Introduction
Blocks, sequences, bow ties, and worms
Combinatorial games
Fibonacci, Pascal, and Catalan
Catwalks, sandsteps, and Pascal pyramids
Unique rook circuits
Sums, colorings, squared squares, and packings
Difference sets and combinatorial designs
Geometric connections
The groups $PSL(2,7)$ and $GL(3,2)$ and why they are isomorphic
Incidence matrices, codes, and sphere packings
Kirkman's Schoolgirls, fields, spreads, and hats
$(7,3,1)$ and combinatorics
$(7,3,1)$ and normed algebras
$(7,3,1)$ and matroids
Coin turning games and Mock Turtles
The $(11,5,2)$ biplane, codes, designs, and groups
Rick's Tricky Six Puzzle: More than meets the eye
$S(5,8,24)$
The miracle octad generator
Bibliography
Index