The following is a list of all The Cat Who... books, in their publication order. An asterisk indicates that the book introduces key characters or locations or otherwise contributes to the development of the series.

Set Down Below
The Cat Who Could Read Backwards (1966) -- Kao K'o Kung (aka KoKo), the first Siamese, enters the picture
The Cat Who Ate Danish Modern (1967)* -- Yum Yum, the second Siamese, makes her debut.
The Cat Who Turned On and Off (1968)
The Cat Who Saw Red* (1986) -- Great character development of Qwill.

Set Mostly in Moose County
The Cat Who Played Brahms (1987)* -- Qwill's move to Moose County.
The Cat Who Played Post Office (1987)* -- sets up the rest of the series.
The Cat Who Knew Shakespeare (1988)* -- introduces Polly.
The Cat Who Sniffed Glue (1988)
The Cat Who Went Underground (1989)
The Cat Who Talked to Ghosts (1990)
The Cat Who Lived High (1991) -- confusing if you haven't read ... Turned On and Off
The Cat Who Knew a Cardinal (1991)* -- introduces Qwill's romantic apple barn.
The Cat Who Moved a Mountain (1992)
The Cat Who Wasn't There (1992)
The Cat Who Went into the Closet (1993)
The Cat Who Came to Breakfast (1994)
The Cat Who Blew the Whistle (1995)
The Cat Who Said Cheese (1996)
The Cat Who Tailed a Thief (1997)
The Cat Who Sang for the Birds (1998)

Still in Moose County, but generally weaker stories
The Cat Who Saw Stars (1999)
The Cat Who Robbed a Bank (2000)
The Cat Who Smelled a Rat (2001)
The Cat Who Went up the Creek (2002)
The Cat Who Brought Down the House (2003)
The Cat Who Talked Turkey (2004)

[Updated April 5, 2004]