It's thirty years since the 1994 genocide against the Tutsis in Rwanda, perpetrated by the Hutu-led government. British journalist Michela Wrong's book Do Not Disturb, The Story of a Political Murder and an African Regime Gone Bad explores the legacy of the genocide, exposing a murderous in-coming regime that operates on a "grand scale deceit", exercising a destabilising influence on the wider region. Michela has reported from and written about Africa for almost three decades, working for Reuters and the Financial Times. Michela is visiting NZ this week, giving a series of talks at the invitation of the New Zealand Institute of International Affairs.

The arrival of photography to New Zealand in 1848 was more about business than art. A cumbersome kit meant photographers needed carriages or horses to lug their gear across unsealed roads to sell their wares. These early images provide a valuable insight to the country's colonial era, with stunning portraits and landscapes now being presented in a new book entitled A Different Light: First Photographs of Aotearoa. Susie is joined by Shaun Higgins who, along with fellow book editor Catherine Hammond, has pulled together the extraordinary and extensive photographic collections of three major research libraries - Auckland Museum, Hocken Collections, and Alexander Turnbull Library. The book is also being celebrated with a travelling exhibition.

Former soldier Christian Lewis had hit rock bottom and was so severely depressed he would shut himself in his flat for weeks. But one day he made an impulsive decision, setting himself the challenge of walking the entire coastline of the UK. Christian joins Susie to talk about his new book, Finding Hildasay, which explores how with just ten pounds in his pocket and a few supplies, he walked himself into a brighter future.

New Zealand's volcanoes are world renowned, and most Kiwis are familiar with our big ones such as Ruapehu, Taranaki and Tarawera. But what about our lesser talked about volcanoes? GNS Science principal scientist Graham Leonard joins Susie to chat about some of the volcanic areas around the country that people are less familiar with - from Northland's periodically active field to volcanoes buried in the Canterbury plains gravels.

You could hardly avoid the gruesome spectacle of the Amber Heard-Johnny Depp trial - it made the nightly news, but it made a much bigger splash on social media. But was there something else at play? Was Amber Heard the victim of an orchestrated campaign of misinformation? Alexi Mostrous of Tortoise Media is a London-based journalist who has previously tackled catfishing and disinformation in his previous very popular podcasts Sweet Bobby and Hoaxed. Alexi joins Susie to talk about how, with the help of a team of data analysts, he dug through hundreds of thousands of tweets to uncover the shocking revelations of his latest series Who Trolled Amber?

New Zealand poet and doctor Glenn Colquhoun has released two new books of poetry in te reo Māori, both accompanied by soundtracks. He tells Susie Ferguson about the legacy of Māori oral poetry and the long process of writing songs he could finally "take to the marae".

Kiwi scientist and champion épée-fencer Dr Matt Baker is representing NZ at fencing in the final Olympic qualifying tournament in Dubai later today. Sydney-based Baker is Scientia Research Fellow in the School of Biotechnology and Biomolecular Sciences at the University of New South Wales, where he studies the molecular motor that makes bacteria swim. But today it's all about the sport and Matt is the sole NZ gladiator in men's épée. Age 41, and father of two young children, he's en garde against some up-coming young stars, all hungry for success at the Asia-Oceania Zonal Qualifier for the Paris Olympics. The men's épée starts at 4pm NZ time, streamed live.

A first of its kind one-to-one support programme for pre-school children showing signs of autism is about to be trialed in Wellington, with aspirations of going nationwide. Professor Josie Barbaro pioneered the most successful tool in the world for the very early detection of autism. Known as Social Attention and Communication Surveillance or SACS, it identifies autistic children aged 11 to 30 months with an accuracy of 83%, and has identified 96% of autistic children by preschool age. Susie is joined by Prof Barbaro and Educational Psychologist and Clinic Lead of the Victoria University of Wellington Autism Clinic, Dr Hannah Waddington. Hannah is rolling out Raupi te Raupo, a world-first free support programme for under fives who, having undergone Josie's assessment, are showing signs of autism.

Saturday morning listener feedback

Kate De Goldi is one of New Zealand's most celebrated authors, an Arts Foundation Laureate, and a voracious reader. She joins Susie to share three books she's loved; Clear by Carys Davies, The Caretaker by Ron Rash, and The Puppets of Spelhorst by Kate di Camillo.