BBC London's Mind the Gap bloggers Steve Phillips and Tom Edwards present their handy Q&A guide to the Tube strike.
Watch the exclusive video above and our two resident travel experts have even taken the trouble to answer extra questions below.
When is the strike taking place?
Three 24-hour strikes have taken place
The first took place on 6 September and the latest started at 1830 GMT on Sunday 28 November.
Services are not expected to return to normal until Tuesday morning.
Why are they striking?
Members of the Transport Salaried Staffs Association (TSSA) and the Rail, Maritime and Transport Union (RMT) are walking out over 800 job losses. London Underground (LU) are making the cuts to ticket office staff to save £16million a year.
There will also be a reduction in ticket office opening hours by 7500 hours in total across the network and six stations are going to lose ticket windows.
LU says there will be no compulsory redundancies and staff will be redeployed. It says sales from ticket offices are down 28 per cent over the last four years due mainly to the success of the Oyster Card.
The unions say fewer staff and ticket office opening hours mean they won't be able to help as many people in particular the disabled and the vulnerable. And this is a "mugger's charter."
Will all Tube services be affected?
In short, most. All Tube lines are suffering some disruption from delays to part or even full suspensions. Best to check what's running/not running before you leave the door.
Our travel team will be in overdrive giving extra updates on the traditional channels - BBC London TV bulletins, extra radio bulletins on BBC London 94.9, and the travel section of this website.
You can also join our commuter community on Twitter, Facebook and there will be more detailed updates on our Audioboo channel.
When was the last time there was a Tube strike and how bad was it?
June, 2009. And it was bad, if you wanted to struggle into work.
A lot of London's faithful commuters worked from home or took time off. The roads were a lot heavier, but the few Tube services that were running were surprisingly quiet!
Are there enough hire bikes to take up the slack?
Up to four million commuters a day use the tube - more than the entire rail network and there are around 4,000 hire bikes all in Zone One.
So, I think while the bikes will probably be busier than ever before, they clearly can't match that kind of capacity. It's not really what they're designed for - they are aimed at short journeys under 30 minutes within Zone One.
But there will be guided cycle rides to help novice cyclists into town from all over London, I'd have thought.
As well as commuters who else loses out from a strike?
The business group London First estimates it costs the capital's economy about £50m a day.
The employees who go on strike don't get paid. LU get no fare box for that day. Industrial relations between employers and employees can sometimes get extremely ugly. Of course, the biggest losers are commuters.
Any winners from the strike?
Yes - black cab drivers, mini-cab firms, pedi-cab cyclists, Thames Clipper boat services, Boris Johnson's bike hire scheme, buses (if you can get on one) and possibly Tom's overtime!
But, no, generally, a Tube strike is just a lot of hassle for everyone.
What happens after the strikes? More strikes? Back to the negotiating table?
After the last few strikes we've had settlements quite quickly with both sides saying the other backed down first and they didn't change their offer. So that's a possibility.
But predicting things in industrial negotiations is a tricky business as you don't know exactly what's going on round the table.
The issue here also is this strike will have national significance.
Many people will be looking at these lay offs and say they show which way other cuts in the public sector will go and how they will play out.
So the stakes become higher and it can then become more about a clash of ideologies, than about head count. And in the current climate, the Unions will not want to lose face.