Strongly influenced by SF pioneer H. G. Wells, Baxter has been a distinguished Vice-President of the international H. G. Wells Society since 2006.
His fiction falls into three main categories, each with a very different style and tone.
His Xeelee Sequence stories are set in the far future, where humans are rising to become the second most powerful race in the universe, next to the god-like Xeelee. Character development in these stories takes second place to the depiction of advanced theories and ideas, such as the true nature of the Great Attractor, naked singularities and the great battle between Baryonic and Dark matter lifeforms. Examples of novels written in this style: Ring, Timelike Infinity.
His present-day Earth stories are much more human, with characters portrayed with greater depth and care. They typically indulge in "if only" whimsy or outright alternate history, dreaming about what humanity could achieve in the exploration of space. NASA features prominently, and a great deal of research has obviously been done into its internal structuring and methods.
However, these novels have a much darker tone than any of his other stories and do not often portray much hope for humanity as a moral species. Examples of novels written in this style include his NASA Trilogy, including Voyage (winner of the Sidewise Award for Alternate History), Titan, and Moonseed; and his as-yet unnamed disaster series, including Flood and Ark.
Each novel of the Manifold trilogy is focused on a potential explanation of the Fermi paradox.
His "Evolution" stories are a later development and show an increasing interest in the evolution of humanity. These seem to have their origins in stories of his other writing styles, such as Mammoth and Manifold: Origin. The novel Evolution is an example of this style.
Baxter also covers numerous other styles: his Mammoth stories, ostensibly for children, are often of great delight to adults, while The Time Ships (an authorised sequel to The Time Machine) is generally taken to be one of his greatest novels. It won the John W. Campbell Memorial Award, the Philip K. Dick Award, the BSFA Award, and was nominated for other major science fiction awards, including the Hugo Award.
In February 2007, Baxter was announced as the author of what was to be the 100th story for Big Finish Productions' Doctor Who audio series. Earthstorm was originally scheduled to be released in late September 2007, but has been delayed indefinitely, according to a May 2007 announcement on the company's website.
In 2009, Baxter became a judge for the Sidewise Award for Alternate History, the first former winner among the panel.
Baxter has also written non-fiction essays and columns for such publications as Critical Wave and the British SF Association's Matrix.