This article from 02138 magazine (H/T: Borjas Blog) gives us the answer - employ teams of researchers to do it for you.
However, as Charles Ogletree, a professor at Harvard Law School, found out, always trusting your RA's in a dangerous game. See article for interesting anecdote.
A Million Little Writers 
When we buy books off best seller lists these days, we almost expect to read the work of more than the named author: his backstage researchers, editors, and agents, maybe even a ghostwriter. Professional athletes admit that they haven’t read the “autobiographies” that carry their names; thriller writer James Patterson has six books coming out this year, thanks to the little-known co-authors who work with him; some popular authors, such as Robert Ludlum and V.C. Andrews, even continue writing books after they’re dead, thanks to the help of hired ghosts.
One might think that the ivory tower should and could resist such commercialism. If nowhere else, the provenance of an idea ought still to matter in academia; the authenticity of authorship should remain a truism. After all, one of the reasons scholars are granted tenure is so they can write free of the commercial pressures of the publishing world, taking as long as they need to get things right. And, whether in the sciences or the humanities, the world of scholarship has always prioritized the proper crediting of sources and co-contributors.
This is all rather odd given the strict rules we have on plagiarism for our students.
This is where it gets depressing though. Young ECONOMICS Professors hires 7 researchers working 70 hour weeks - makes competing with such fellows rather difficult.
Because, in any number of academic offices at Harvard, the relationship between “author” and researcher(s) is a distinctly gray area. A young economics professor hires seven researchers, none yet in graduate school, several of them pulling 70-hour work-weeks; historians farm out their research to teams of graduate students, who prepare meticulously written memos that are closely assimilated into the finished work; law school professors “write” books that acknowledge dozens of research assistants without specifying their contributions. These days, it is practically the norm for tenured professors to have research and writing squads working on their publications, quietly employed at stages of co-authorship ranging from the non-controversial (photocopying) to more authorial labor, such as significant research on topics central to the final work, to what can only be called ghostwriting.
The article goes on to blame Harvard for leading a bad example. The clear culprit is opportunity cost - Harvard professors can earn a lot more doing consultancy that they do this while ensuring a steady stream of publications by using some of the extra money to hire research assistants (who will be good by definition as they are at Harvard).
“The celebrity professor is a new phenomenon and not a good one,” says Lewis. In celebrity-driven academia, “getting ahead … means beating other people, which means establishing a personal reputation and denying it, to the extent possible, to rivals and even to assistants.
Clearly this celebrity gravy train is one worth riding in the US:
Outsourced work is partly a response to time constraints; it allows a professor to both produce more—more books, more op-eds—and have more time for non-research work, such as appearing on television, taking on pro bono legal cases, and starting research centers. With such aims, a professor is often pursuing fundamentally different goals than the pursuit of knowledge: The frequent publication of quickly written popular books generally has more to do with the pursuit of fame and material success. Publish the book, land on TV, sign up with a speaker’s bureau for five figures a speech, maybe even get appointed to corporate and charitable boards. Suddenly, your income in the low six figures can double or triple.
Anyone think a book on "Globalisation and the Environment" will sell?
Feel free to out any academic economists out there that outsource their books and research - perhaps they all do and I am the last to know?