Theresa May's Withdrawal Agreement will almost certainly be defeated tonight, but the votes immediately beforehand could shape the future of the process.
Here's who tabled the amendments and what they say:
1 - Jeremy Corbyn's soft Brexit amendment
The Labour leader's offering rejects the Prime Minister's deal and sets out a softer alternative Brexit, which would see Britain remain in a customs union with the EU. It also calls for guarantees on workers' rights and environmental standards.
2 - SNP and Plaid Cymru's extension amendment
The SNP's Westminster leader Ian Blackford and others also want MPs to reject the Government's deal, saying it damages the UK's regions, and demand an extension to Article 50.
3 - Edward Leigh's backstop amendment
Tory backbencher Sir Edward Leigh recently became a convert to May's Brexit deal after being made a privy councillor. His proposal to MPs is to impose a time limit on the troublesome Northern Irish backstop. The EU would have to agree to it of course, but a big show of support from MPs could pile on the extra pressure needed to get further concessions from Brussels.
4 - John Baron's backstop amendment
Conservative MP John Baron's plan also addresses the backstop. It would give the UK the power to unilaterally end the arrangement without agreement from the EU. I think it's safe to say Brussels would not be keen.