Unsurprisingly, this tale of power, greed, and corruption begins (and ends) with the Medici, that ruthless mafiosi family of bankers whose spawn ascended to become Europe’s queens, dukes, and popes. The Medici’s rise coincided with the burgeoning wealth of the Italian city-states, where the ‘father of accounting’, Luca Pacioli, authored his ground-breaking Summa de arithmetica (1494), which institutionalised the practice of double-entry accounting. The flourishing, Florence-based Medici banking network enveloped the continent, but it was the accountants who determined which parts of the business were profitable, and which managers were dishonest. Ever the innovators, the Medici created corporate networks, ensuring one part of the franchise was sufficiently autonomous to fireproof the rest of the business from risk. Every modern multinational corporation has duplicated the Medici model; James Hardie Industries learned this lesson well.

Gow and Kells’s argument is clear: the Big Four, like the major banks, are systemically important to the functioning of global finance. Accountants and auditors were critical to the embryosis of the nation-state in the sixteenth century and formed a symbiotic relationship with both government and finance throughout the last 500 years. Recall how French finance ministers Turgot and Necker tried in vain to save Louis XVI from bankruptcy until the revolution and the guillotine severed the link between the monarch and his money. Permanently.

Imagine the clubby atmosphere of nineteenth-century British high finance: the richly-panelled walls; vintage Chesterfields in aged buffalo hide; and the grey men (no women) in suits. Through wafts of cigar smoke, one might discern the Big Four’s founders: Edwin Waterhouse, Samuel Price, William Deloitte, Frederick Whinney (EY), and James Marwick and William Peat (KPMG). This was the heyday of J.P. Morgan and the Rothschilds in the era of the nineteenth-century robber baron. Morgan even owned the Titanic (and her two sister ships), through one of his notorious trusts, just to emphasise how wealthy he really was.

This kind of conspicuous consumption has long merited attention, evidenced by innumerable bank biographies. But curiously, the bankers’ bookkeepers – the accountants – have been overlooked by financial historians; perhaps this is the way the auditors prefer it. There are few tomes focusing upon the chequered history of these behemoths. Gow and Kells’s story of the ‘Big Four’ accounting firms serves as a useful corrective, filling in an important gap in the literature.

Pontormo, Portrait of Cosimo de Medici the Elder, ca. 1518 (Uffizi Gallery, Wikimedia Commons)Governments for half a millennium have recognised how important accountants are to their financial and fiscal stability. Thus, accountants were welcomed into the ranks of other professionals, such as scientists, teachers, doctors, and priests: the state’s ‘foot-soldiers of integrity’. Indeed, many nineteenth-century accountants were fraud-busters par excellence; William Deloitte and Edwin Waterhouse uncovered numerous lies and deceptions in the booming railway industry, and their efforts not only brought about parliamentary legislation, but also the establishment of mandatory double-entry accounting in Britain in 1868.

The Big Four audit ninety-nine per cent of the world’s major corporations. No other financial oligopoly enjoys such a level of market dominance. But this hydra has grown many heads; PwC employs 2,400 lawyers in eighty-nine countries, while Deloitte has 1,300 lawyers in fifty-six countries. Unsurprisingly, law firms are deeply unhappy about this encroachment on their turf. As the authors note, the increasingly beleaguered legal industry has accused the accountants of ‘surrogate’ law practices, prompting defensive ‘Big Law’ mergers globally.

The Big Four’s tentacles are not only wrapped around the legal industry; they have also assumed a vice-like grip upon the lucrative ‘advisory’ market, challenging traditionally dominant players, such as McKinsey’s and Boston Consulting. By the beginning of the twenty-first century, advisory accounted for almost half of the revenues of all of the Big Four. By 2013 more than half of Deloitte’s revenue came from consultancies.

There were sound commercial reasons for transitioning to consulting. The problem with accounting as a business is that it relies upon a mad rush during peak periods. Consulting is also attractive because it provides a solution to the vagaries of the business cycle; how can an accounting firm take advantage of busts as well as booms? The answer lay in entering the insolvency market, thus ensuring accountants truly became men for all seasons.

In China, the Big Four’s expansion saw the government grow deeply resentful of what it saw as plenipotentiaries of American regulatory power trampling on China’s economic sovereignty. Western accounting firms were likely gathering far too much sensitive ‘national economic information’ as well. In 2007, the Chinese Securities Regulatory Commission responded in classic Politburo form: it created a raft of competing Chinese corporations to take on the Big Four.

But will they last? Gow and Kells argue that the Big Four are vulnerable, particularly to litigation. It is clear the authors see a GFC-type contagion effect engulfing the Big Four, just as established banks collapsed in 2008. Congress has recommended all of the Big Four prepare ‘living wills’, like banks, for the orderly transfer of clients and contracts in the event of their demise. They are obvious targets for anti-trust laws, which may force them to spin-off their accounting, auditing, or consulting businesses. More ominously, digital disruption looms, with the routine tasks of accountancy likely to be replaced by artificial intelligence imbued with smart algorithms. In 2016, EY predicted it might halve its junior intake by 2020.

Gow and Kells have avoided writing dry, academic corporate biographies. Instead, they have produced an engrossing book full of illuminating and sobering facts. It deserves a wide readership.