It will be a second fortune for Peter Dyer, Crystal's chief executive. After founding the business in 1981 he sold it to Dial Corporation, an American group for around pounds 4m in 1991. He bought it back for less than pounds 30m last October in a venture capital deal, and has now more than doubled his money in less than a year.
Mr Dyer, 47, will make pounds 11m from selling Crystal for a second time.
Crystal is Britain's leading ski holiday company, and with Thomson already ranked three in winter sports, the deal makes it a powerful player in the sector. It also gives Thomson positions in specialist vacations, such as lakes and mountain holidays, coach breaks and trips to Jersey, Italy and France.
This is the latest in a series of deals in the UK travel industry, which is rapidly consolidating around the three largest players.
In the last few months First Choice Holidays has snapped up Unijet and Hayes & Jarvis; Airtours has acquired Direct Holidays; and Sunworld, part of Thomas Cook, has bought Flying Colours, the travel business which includes the Club 18-30 operations.
"The Crystal deal is part of the on-going consolidation in the sector," said Jason Holden, who is a leisure analyst at BT Alex.Brown. "It leads to economies of scale, great buying power, and, in this case, it gives Crystal access to Thomson's airline."
Paul Brett, chief executive of Thomson, which floated on the stock market in May, said that the deal was part of its strategy to mirror its market leadership in mass market holidays with a similar position in specialist areas, such as skiing and city breaks.
However, he said the surge of deal making in the UK was drawing to a close. "There are not many medium-sized companies left," he said.
Crystal's businesses include Jetsave, which specialises in American holidays; Tropical Places, a direct sales operation; Crystal Ski; and Greyhound International, which books seats on American greyhound buses.
Crystal is expected to record profits of around pounds 3.4m in the year to October on sales of pounds 200m-plus.
It is expected to sell more than 400,000 holidays this year.
Mr Dyer will stay on as chief executive of the business, which will be merged with Thomson's specialist tour operation.
Thomson is funding the deal from existing resources.
The shares, floated at 170p, fell 3.5p to 154p.