Hjalmar Schacht is, Hitler aside, the protagonist of the book's early chapters. In the Weimar era he was a political liberal squarely within Stresemann's camp and worked at the helm of the Reichsbank and as one of Germany's reparation negotiators until his replacement by Hans Luther in spring 1930. At about the same time he had grown disappointed with the Young Plan, disillusioned with Atlanticist diplomacy and hoped for a more agressive foreign policy and debt negotiation. He aligned with the radical right but didn't overtly criticize the Bruening government in hope of getting a cabinet position until 1931, when unemployment was massive and banks were collapsing. He appeared alongside Hitler at a nationalist rally in Bad Harzburg. He was now in Hitler's camp and took part in his February 1933 meeting with industrial magnates. With Hitler in power he naturally returned to the Reichsbank's presidency.
From this position he wielded immense power. He embraced unorthodox economic solutions, earning him the moniker of "dark wizard", though not work creation, a point he had to concede to Hitler. He took part in debt negotiations with the Western powers and was the architect of Mefo bills and the Reichsbank's final import control system. Its establishment required him to outmaneuver Kurt Schmitt, head of the RWM, and Hans Posse, senior civil servant at that Ministry, who had an alternative "Krogmann plan" with a pseudo-market mechanism for managing import rations. With Thomas and Keppler as intermediaries, Schacht spoke to Hitler at a music festival in Bayreuth, 1934, and won his support by promising resources for rearmament. Tooze then recounts:
Encountering Secretary of State Posse for the first timein his new offices, Schacht asked him: 'Are you interested in music?' To which Posse innocently replied: 'Yes, very.' Schacht's retort was typically sarcastic: 'I'm not at all musical, but I was in Bayreuth.' (p.85)

Schmitt, a moderate, couldn't stand the Reich's 1934 crisis. Prior to the Night of the Long Knives he even feared a coup by the SA against him, as he was hated in National Socialism's left wing. He couldn't even physically bear the pressure:
By the early summer, Schmitt's health was collapsing under the strain. The end came on 28 June during a routine after-dinner speech to an audience of Berlin exporters. The Minister began by setting out the extremely serious situation facing the German economy and asked: 'What is to be done?' Before he could answer his own question, the blood drained from his face and he collapsed in mid-sentence. The water from his glass dribbled across the pages of his speech. (p.71)
From 1934 to 1937, Schacht succeeded him as Acting Minister (not permanent, as the Reichsbank was meant to be independent). With both the Reichsbank and the Reichswirschaftministerium (RWM), he accumulated immense power. The RWM was at the top of the group hierarchy of firms, encouraged (or forced) cartel formation, regulated prices, negotiated trade deals and so on.
Together, the Reichsbank, RWM and RFM became a pro-business bloc within the regime.
Schacht's support of rearmament came back to bite him. Already in 1936 he became Keppler's enemy by opposing his plan to mine low-grade German iron ore deposits. By 1938 he opposed the intense rate of rearmament because of its overwhelming pressure on the system he had carefully built. He fell to the sidelines and lost both of his positions, which by 1939 were under Walther Funk, loyal to Hitler but not as brilliant.
Tooze characterizes Schacht as a man of action but also an opportunist. He sometimes slips his opinion on Schacht's personality, such as
As Schacht put it with characteristic charm: 'One can sell far less to coolies .. . than one can to highly qualified . .. factory workers.' (p.89, on Germany's trading partners in South America and the Balkans).