The Interlopers (novel)

The Interlopers, first published in 1969, was the twelfth novel in the Matt Helm spy series by Donald Hamilton, which began in 1960. It represents a middle period in the Helm novels, being about 80,000 words in length, somewhat longer than the first four or five in the series, but considerably shorter than most of the Helm books of the eighties and nineties, which were generally well over 100,000 words in length. At this intermediate length, the action moved swiftly while still allowing for plot complications, but avoided the occasional padded-out-by-dialogue tedium of the later books.