A Bitter Field — David Donachie

The final installment in Donachie's sweeping Roads to War series set in the pre-WWII European powder keg

1938: As Hitler sets his sights on the Sudetenland, not everyone in Britain is willing to appease him. Convinced that the Führer's land hunger is insatiable, the head of the SIS recruits Cal Jardine to help him prove that Czechoslovakia is threatened with invasion. But before heading undercover to Prague, Jardine must first extricate himself from France, where his attempts to smuggle guns to Spain have been held up by a group of fanatical fascists. In their struggle to overthrow the French government, they are prepared to kill for the sake of procuring weapons.

When Cal finally arrives in Czechoslovakia, working undercover for the SIS proves no less dangerous as jealousy and mutual suspicions within Secret Service ranks make it impossible for him to tell friend from foe.