Binge-drinking, bullying and licentious corporate bonding sessions are all explicitly recounted by the author, a 27-year-old solicitor who claims his book is based on events that took place at one of London's biggest law firms.
The partners are portrayed as sex-obsessed and sadistic, while female lawyers are judged by the size of their breasts rather than their legal acumen.
Now the hunt is on to find the firm at the centre of the novel and unmask the identity of the author who has written Fish Sunday Thinking under the pseudonym Alex Gilmore - one legal website is even running a competition on the subject.
It is a mystery which has prompted comparisons with Belle Du Jour, the best-selling diary of a call-girl whose identity has never been revealed.
Unsurprisingly, Fish Sunday Thinking has caused consternation within the ranks of the £1m-a-year lawyers who run the so-called "magic circle" firms.
Speaking to The Independent on condition of anonymity, "Mr Gilmore" said his former bosses had plenty to be worried about.
"My book is typical of what goes on in many City law firms. Sex is used as a currency to advance careers and junior lawyers who don't play ball find themselves out in the cold."
He added: "I know of at least four or five incidents in which a partner has taken advantage of a trainee lawyer for his own sexual gratification.
"What you have to remember is that the partners are like gods who have enormous power over you. If you make a fuss you suddenly find yourself on permanent photocopying duty. And anyone who has the guts to make a complaint ends up out of a job and without suitable references. It's hardly surprising that so few people go public."
In one scene in Fish Sunday Thinking, (the title refers to the dread of returning to work after the weekend), a group of corporate lawyers on a bonding weekend retire to a bar where the partners take it in turn to use their tongues to extract a slice of lemon from a trainee's cleavage.
In another episode one of the lawyers describes waking up in bed with two of the firm's legal secretaries.
Mr Gilmore, who now works for a solicitors' practice in the Midlands, says he wrote the book because he wanted to warn other lawyers of what they were letting themselves in for if they decided to join a City law firm.
"All my time was spent photocopying. I soon realised I was just a paper-pusher on a good salary. But I was so unhappy I was spending 80 per cent of my salary on alcohol. Drink was all that was left at the end of another soul-destroying, 18-hour day."
He said: "I was amazed to find that girls were judged on their looks. There were lots of examples of pretty girls being promoted over the heads of less attractive but more able colleagues. And there were affairs between senior male lawyers and younger trainees. Senior partners would talk quite brazenly about girls, comparing their cleavages, their legs, their bottoms. It was accepted that good-looking women had first refusal on the best jobs. The argument was that clients liked pretty women and everything was about keeping the client happy."
It appears "Mr Gilmore's" experience is not unusual. More than 100 young lawyers have responded to a competition on the legal profession website, rollonfriday.com, which invited examples of real-life comparisons with the book.
Matthew Rhodes, who runs the website, said: "I take my hat off to Alex for exposing this. But anyone who reads the news on rollonfriday.com or looks at our discussion board will know that this sort of thing happens at pretty much every City firm on a daily basis."
Some of the more extreme incidents have ended up before an employment tribunal. In 2004, Elizabeth Weston, 29, a lawyer at Merrill Lynch, the investment bank, received £1m in an out-of-court settlement over her claim against the company over lewd remarks made to her by a colleague at a Christmas party.
A City law firm had to pay out £10,000 to a black secretary after two of its lawyers complained that what they really wanted was a "fit busty blonde secretary" to replace her.
With these cases in mind, it will be difficult for law firms to dismiss "Mr Gilmore's" allegations as pure fiction.
Mr Rhodes says he knows who "Mr Gilmore" is and the firm that he worked for. "I have given him my word that I won't tell," he said.
Senior partners in charge of the top London law firms will be hoping that the name of the firm remains secret. A partner at one of the main London law firms said: "If it turns out to be us then the proverbial excrement will truly hit the fan."Reuse content