Gavin Francis has a remarkable pedigree as a medical writer. He has been a paediatrician, an obstetrician and a doctor in a geriatric ward. He has also been a medic on Arctic and Antarctic expeditions and worked in community clinics in Africa and India, before ending up in a family doctor’s clinic in Edinburgh. For good measure, he is also an award-winning travel writer.

This, in short, is a man who knows his way around the world, and the human body, and also knows how to write about it. The end result is the admirable Adventures in Human Being (Wellcome Collection), my choice for science book of the year.

Described as a grand tour of the human frame, the book – made up of 18 essays, each devoted to a particular organ – begins at the brain and heads downwards through the inner ear, kidneys, lungs, rectum – “a magnificent work of art”, we are told – the liver and the genitalia, before finally reaching the feet and toes, which Francis describes as “a marvel” of engineering. “When we run,” he says, “around half of all the energy used in each step is stored in the elasticity of our achilles tendon and sprung into the arches of the feet.”

This last feature allowed early humans to evolve upright locomotion and freed our hands so we could carry objects and manipulate the environment around us. That in turn led to the evolution of larger and larger brains, which were needed to control our actions and make sense of the world. Think of this, then, as the feet-first school of evolutionary thinking.

Into this mix of ideas, Francis then adds his own experiences as a medical practitioner, often to wry effect. During one stint in a hospital A&E department, Francis asks a powerfully built patient, who is nursing a shattered fist, for his profession. “A pickpocket. What is it to you?” the patient snarls. “Just checking you’re not a concert pianist,” Francis responds.

It is enjoyable, eloquent fare, often amusing, sometimes moving, but always informative. As Francis says: “Learning about the human body is different to learning about anything else: you are the very object of attention, and working with the body has an immediacy and transformational power that is unique.”

Matthew Cobb’s Life’s Greatest Secret: The Story of the Race to Crack the Genetic Code (Profile) tells the tale of the group of scientists – mainly French, British and American researchers – who first showed that DNA was the critical constituent of our genes and revealed that it had a double helical structure. Then they went on to demonstrate how that double helix controlled the manufacture of amino acids from which our bodies’ proteins are constructed. This is the genetic code.

“Cracking the code was a leap forward in humanity’s understanding of the natural world... akin to the discoveries of Galileo and Einstein in physics, or the publication of Darwin’s On the Origin of Species,” Cobb tells us in this absorbing, meticulous account of one of the greatest scientific stories of the 20th century. Hundreds of scientists were involved in an effort that can be compared in size to the team behind the Apollo moon landings – except they had no leadership, no overseeing council, and no directed funding from governments pursuing military or political goals. Instead they relied on brilliant insights, audacious experiments and, above all, a lot of hard work. It’s a tremendous story.

Introduced by Kierkegaard’s aphorism that “life must be lived forward but can only be understood backwards”, Oliver Sacks’s autobiography, On the Move: A Life (Picador), is a touching account of the life of a neurologist and writer who did more than anyone to extend our understanding of mental illness. His death, not long after the book’s publication, robbed us of a rare talent. The story of his life is revealing and absorbing.

On the green front, the weeks leading up to the climate change summit that is now being held in Paris also saw the publication of several first-rate books about the challenges facing our planet as global warming takes a grip of it. Of these, Tim Flannery’s Atmosphere of Hope: Solutions to the Climate Crisis (Penguin) and Oliver Morton’s The Planet Remade (Granta) most successfully balance the difficult business of raising alarm about the dangers ahead – flooding, starvation, ocean acidification and mass migration – with proposals for the types of action we need to take now to head off catastrophe tomorrow.

However, my favourite environmental offering this year is Patrick Barkham’s Coastlines (Granta), an eloquent account of his travels round the British Isles that perfectly catches the wonder of the British coast. As Barkham notes: “Every day, there is something surprising, joyful and new to be found beside the sea.” An uplifting read.

Save at least 30% Browse all the critics’ choices at bookshop.theguardian.com or call 0330 333 6846. From now until Christmas, 20p from each title you order will go to the Guardian and Observer charity appeal 2015.

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