Excerpt from A Spy Among Friends by Ben Macintyre, plus links to reviews, author biography & more

The friendship between Philby and Elliott was not just one of shared interests and professional identity, but something deeper. Nick Elliott was friendly to all but emotionally committed to few. The bond with Philby was unlike any other in his life. "They spoke the same language," Elliott's son Mark recalls. "Kim was as close a friend as my father ever had." Elliott never openly expressed, or demonstrated, this affection. Like so much of importance in the masculine culture of the time, it was left unsaid. Elliott hero-worshipped Philby, but he also loved him, with a powerful male adoration that was unrequited, unsexual, and unstated.

Their relationship grew still closer when both were plucked from the outer reaches of British intelligence and placed at the very center, in Section V of MI6, the division devoted to counterintelligence. MI5 was responsible for maintaining security, including the combating of enemy espionage, within the UK and the British Empire. MI6 was responsible for gathering intelligence and running agents abroad. Within MI6, Section V played a specific and vital role: collecting information on enemy intelligence in foreign parts, by means of spies and defectors, and furnishing MI5 with advance warning of espionage threats to Britain. A vital link between Britain's secret services, Section V's task was to "negate, confuse, deceive, subvert, monitor or control the clandestine intelligence collection operations and agents of foreign governments or agencies." Before the war, the section had devoted most of its energies to monitoring the spread of international communism and battling Soviet espionage, but as the war progressed, it came to focus almost exclusively on the intelligence operations of the Axis powers. The Iberian peninsula was a particular concern. Neutral Spain and Portugal stood on the front line of the espionage war. Many of the German intelligence operations directed at Britain were launched from these two countries, and in 1941 MI6 began beefing up the Iberian operation. One evening Tommy Harris told Philby that the bosses were looking for someone "with a knowledge of Spain to take charge of the expanded sub-section." Philby immediately expressed an interest; Harris spoke to Richard Brooman-White, Elliott's old friend, the chief of MI6's Iberian operations; Brooman-White spoke to the head of MI6. "The old boy network began to operate," as Philby put it, and within days he was summoned to see the head of Section V. Major Felix Cowgill was the model of the old-style intelligence officer: a former officer in the Indian police, he was rigid, combative, paranoid, and quite dim. Trevor-Roper dismissed him as a "purblind, disastrous megalomaniac," and Philby, privately, was equally scathing. "As an intelligence officer, he was inhibited by lack of imagination, inattention to detail and sheer ignorance of the world." Cowgill was "suspicious and bristling" toward anyone outside his section, blindly loyal to those within it, and no match for the Philby charm.

Philby never formally applied for the job, and Cowgill never formally offered it, but after one long, bibulous evening, Philby emerged as the new head of Section V's Iberian department, a job that, as Philby happily noted, entailed wider responsibilities as well as "personal contacts with the rest of SIS and MI5." Before Philby took up the post, however, Valentine Vivian, known as "Vee-Vee," the deputy head of MI6, decided to have another chat with Philby's father. Hillary St John Bridger Philby was a figure of considerable notoriety. As adviser to Ibn Saud, the first monarch of Saudi Arabia, he had played (and would continue to play) a key role in the oleaginous politics of that region. He had converted to Islam, taking the name Sheikh Abdullah, spoke Arabic fluently, and would eventually marry, as his second wife, a slave girl from Baluchistan presented to him by the Saudi king. He remained, however, quintessentially English in his tastes and wildly unpredictable in his opinions. The elder Philby's opposition to the war had seen him arrested and briefly imprisoned, an episode that did no harm to his own social standing or his son's career prospects. Over lunch at the club, Colonel Vivian asked St John Philby about his son's politics.

Excerpted from A Spy Among Friends by Ben Macintyre. Copyright © 2014 by Ben Macintyre. Excerpted by permission of Crown. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.