Moving to academia from industry I hope that the following question is suitable for MO. There have been several others in a similar vein, including this one about moving from maths into industry, this one about careers advice for mathematicians and this about returning to graduate school after a couple of years in industry (among others). My situation is a bit different from those discussed in the referenced questions, as I am interested in moving from an already well-established career into academia.
I'll give a bit of background about myself. Naturally, this will be rather personal to my situation but, maybe, the general question could also be of interest to others.
I already have a PhD in maths from a top university and, now, have quite a successful and well paid career in industry. The reason for moving in the first place was complicated and influenced by several factors. Money was certainly one of them, as I was virtually skint at the time, but the main reason was that I was just not happy with my lifestyle at the time and was wanting a complete change. This was over ten years ago.
However, after family, my main interest in life is maths. While it was fun initially to work in a highly technical field in industry, over the past few years I have found myself getting bored. Throughout my time working, I have been keeping up my interest in maths, mainly by reading books and papers, but also by writing a small number of papers independently. I had a couple published, and a couple more accepted but, between family life and work, have not had time to pursue this further. More recently, I have started writing a blog, and have been contributing to this site. I would like to say that I have been attending lectures or seminars at one of the top universities around here, as it is something that I have always been intending to do, but have had very little time to actually organize doing.
My question then, is what are the options for moving back into academia after spending a significant time in industry? Also, as time is moving on, I think that moving back into academia at the point where I left off - having just completed a PhD - would not be ideal. I certainly feel ready to contribute to the mathematical community at the highest level.
One answer, I suppose, is simply to speak to the people I worked with during my PhD. That is not so simple though. The people I worked most closely with have since moved on (either into industry themselves, or retired) and I am not so sure about suddenly contacting people who I never worked very closely with after such a large gap. That is certainly something I am considering, but would first like to get some opinions from the wider mathematical community. I am based in the UK, although any opinions based on experience elsewhere could also be valuable.
Finally. I have been quite active on this website under my real name. However, I do not think it is wise to openly talk on the internet about possibly leaving my current career, so am posting this question anonymously.
 A: The answer will depend significantly on the country you're in, and of course with the current economic situation, need I mention that this is not the best time to jump ship? Overall, I think it would be difficult to get the kind of research position you may have had after the PhD, and a lot easier to leverage your industry experience into a position related to your current field (which I realize may not be quite what you're looking for). That's even assuming that the university system you're thinking about even cares about industry and giving students job skills that are current, which is where your mileage may vary tremendously, especially from country to country. 
Oh, and BTW I doubt that your MO activity will be all that useful in your transition. Still, thanks for contributing!
A: I hope I am not being presumptuous here, but I thought I'd cast my inexperienced, untempered opinion.
Maybe applied math, scientific computing, computational science, computer science, financial math, or statistics departments might be more flexible? I believe the transition will be difficult, but it also very strongly depends on what kind of mathematics you are into; also relevant here would be for example what type of industrial experience do you have, a research lab, or a more applied place, and so on.
On a more pragmatic note, maybe you could first try to obtain a "visiting professor" or "research visitor" position at some preferred university, to see if you really like academia --- so that you save yourself unpleasant surprises because the ground reality might differ a lot from what you might imagine?
Good luck.
A: Since no one else has mentioned it, I think the best thing to do is meet people.  If it's possible, go to conferences or visit departments (might it be possible to get an unpaid leave without quitting your job?) and meet people.  You're going to both want personal contacts in departments where you might like a job, and you'll need people to write you letters of recommendation.  Assuming you don't act extremely offensive in person or embarrass yourself, this can only be for the good.
A: Perhaps an option is to first become a (part-time?) tutor at an Oxford or Cambridge University college (provided these are not too far away); some of the colleges may indeed appreciate your industry experience.  
There might be similar positions at other English universities, of course. 
A: Nobody seems to have mentioned much about teaching--- perhaps because the original question itself makes no mention of teaching having anything to do with the desire to return to academia.  This is a kind of elephant in the room.  
I should admit: I'm on the academic side, I have not personally tried to make this kind of transition, and I have never been in a position to evaluate somebody making this kind of transition.  But it seems to me that if you're reasonably current with your research area, and publishing papers, and meeting people (as suggested elsewhere), your biggest obstacle may be teaching.
Presumably you have no teaching experience over the last n years, and depending on your grad school experience, you may not have had much then (or it may have been a different sort from what professors do).  This may matter.  I don't know how to begin building a teaching history, while working a full-time job.
You may need to overcome the suspicion that will find teaching low-level service courses boring for the same reasons you find your current job in industry boring.  Imagine the skeptic on the search committee who asks, rhetorically, "Who wouldn't be an academic if it were all just learning, writing papers, and talking to enthusiastic people with the same interests?"
Even with stellar references and a personal connection or three in the department, someone will ask: can you teach?  Do you want to?  What's the answer, and how do you convey it on your CV?  
I don't have specific advice in this area, because it depends on where you want to work, and your own background.  If it is possible to do pedagogical things in your current job, or service/outreach to non-specialists or students, perhaps that would help.  Maybe actual teaching (on a per-course basis, not as tenure-track faculty) or volunteering would help.  My feeling is that you need to do something to address these issues head-on, to confront both any genuine gaps in your CV, and the biases and prejudices you may face simply because you are changing careers.
