In our online poll to find out what Plus readers would most like to know about the Universe, you told us that you'd like to find out what happened before the Big Bang. We took the question to the renowned cosmologist John D. Barrow and here is his answer. The Universe is an infinitely self-perpetuating foam of bubbles, it seems. This podcast accompanies the article What happened before the Big Bang?.

We talk to Professor Robin Wilson, author of the book Lewis Carroll in numberland, about the mathematical work of the famous author of the Alice books, whose real name was Charles Dodgson.

What do the human brain, the Internet and climate change have in common? They're all hugely complex, and while they're very different, the tools used to grapple with this complexity are likely to be similar. We visited the Cambridge complex systems consortium, dedicated to building an over-arching science of complexity, and talked to neuroscientist Ed Bullmore, mathematician Frank Kelly and climate scientist Hans Graf about their take on complexity. This podcast accompanies the article Catching terrorists with maths.

According to media reports there are two suspects in the dock: the rocket scientists' (a.k.a. the financial mathematicians) who provided the information behind the market's decisions, or the greedy bankers who only thought about quick profits and their end-of-year bonuses. We talk to David Hand, Chris Rogers and John Coates to find out who is guilty. This podcast accompanies the article Is maths to blame?

Chuck Gill caught the space bug as a child when watching Alan Shepherd launch into space. Since then he's worked as a US Air Force navigator, a satellite operator, and in the US intelligence service. These days he's busy reducing carbon emissions and preparing London for the 2012 Olympics. Plus went to see him to find out more about his career. This podcast accompanies the career interview from issue 48 of Plus.

Peter Markowich is a mathematician who likes to take pictures. At first his two interest seemed completely separate to him, but then he realised that behind every picture there is a mathematical story to tell. Plus went to see him to find out more, and ended up with an introduction to partial differential equations. This podcast accompanies the article Universal pictures.

The Fourier transform is a piece of maths that is, almost single-handedly, responsible for the digital revolution. Digital music and images would be impossible without it and it has applications in anything from medical imaging to landmine detection. We asked Chris Budd what the Fourier transform does, and how it does it. This podcast accompanies the Plus article Saving lives: The mathematics of tomography.

Maths has long been a theme in the movies. This week, Plus talks to Madeleine Shepherd, organiser of the maths film festival at the recent Edinburgh science festival, about how maths has been presented in the movies over the years, with particular reference to three more recent films, Cube, Pi and Flatland. For more on maths in the movies read the Plus article Maths, madness and movies.

This podcast accompanies the career interview in issue 47 of Plus. Barry Phipps is the first interdisciplinary fellow with the Kettle's Yard gallery in Cambridge. His remit is to develop projects of an interdisciplinary nature, to find the common ground between things. This week, Plus talks to Barry about breaking down the barriers between artists and scientists and creating greater dialogue because, as Barry says, science and art are intrinsically related at the centre, and there is no stepping away from one to be another.

From the complexity of the snowflake, to the London tube map and the spiralling Andromeda galaxy, imagery has always been a vitally important ingredient of science. This week, Plus talks to John Barrow, professor of mathematics at Cambridge University and author of the new book Cosmic Imagery, about the images that have changed science, and how we have viewed science, over the centuries.

The Enigma machine was once considered unbreakable, and the cracking of the "unbreakable code" by the allies changed the course of World War 2. This week, Plus talks to Nadia Baker from the Enigma Project about the history of codes and code-breaking, why the Enigma machine was considered unbreakable, the mathematics behind codes, and how it was finally cracked. The Enigma Project travels all over the United Kingdom and abroad, visiting over 100 schools and organisations, reaching over 12,000 people of all ages every year.

Bacon sandwiches, drinking while pregnant, obesity - health risks are a favourite with the media. But behind the simple numbers quoted in the headlines lies a huge and sophisticated body of statistical research. We talk to Professor Sheila Bird of the Biostatistics Unit in Cambridge about her work in public health and its impact on policy, and discuss bias in pharmaceutical studies, as recently highlighted by the controversy around antidepressants.

We talk to four researchers from UCL's centre for mathematics and physics in the life sciences and experimental biology (COMPLEX) about the role of maths in such fields as astrobiology, cancer modelling and biology.

We talk to Nira Chamberlain about his job as a modelling consultant involving aircraft carriers, telecommunication networks, staying slim and speaking French.

We talk to Professor Chris Budd about the greatest mathematician of all - Leonard Euler. We also talk about maths communication, maths in the food industry and the best mathematical pickup lines.

We visit the European Women in Mathematics conference and talk to two leading mathematicians, Caroline Series and Cheryl Praeger.

Reidun Twarock finds symmetry in viruses and tells us about the maths used to understand them.

We talk to Shahn Majid about a whole new geometry of space, find out about how mathematics is combatting climate change, as well as all the latest news from the world of maths.