Rainbow Six

Rainbow Six is a techno-thriller by Tom Clancy, released on 3 August 1998. It is the second novel to centre on John Clark, one of the recurring figures in the Ryanverse, after Without Remorse in 1993, and it also features his son-in-law Domingo Chavez, known as Ding.

The organisation at the centre of the book is Rainbow, a secret international counterterrorist unit commanded by Clark under the codename Rainbow Six. Its early operations present a series of apparently unrelated attacks, and the plot is the work of establishing the pattern behind them until an apocalyptic conspiracy becomes visible. The novel is built as an investigation from the operators' side rather than as a race against a single known enemy.

It debuted at number one on the New York Times Best Seller list. Reviews were mixed, praising the action and suspense while criticising the treatment of some characters and judging the plot implausible, and the book drew criticism from the environmental movement for its depiction of radical environmentalism. Clark, Chavez and Rainbow returned in Clancy's next novel, The Bear and the Dragon, in 2000.