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```{currentmodule} tskit
```

(sec_introduction)=

# Introduction

This is the documentation for `tskit`, the tree sequence toolkit.
Succinct tree sequences are an efficient way of representing the
genetic history - often technically referred to as an Ancestral
Recombination Graph or ARG - of a set of DNA sequences.

The tree sequence format is output by a number of external software libraries
and programs (such as [msprime](https://tskit.dev/msprime/docs), 
[SLiM](https://github.com/MesserLab/SLiM), 
[fwdpp](https://fwdpp.readthedocs.io/en/), and 
[tsinfer](https://tskit.dev/tsinfer/docs/)) that either simulate or
infer the evolutionary ancestry of genetic sequences. This library provides the
underlying functionality that such software uses to load, examine, and
manipulate ARGs in tree sequence format, including efficient access to the
correlated sequence of trees along a genome and general methods to calculate
{ref}`genetic statistics<sec_stats>`.

For a gentle introduction, you might like to read "{ref}`tutorials:sec_what_is`"
on our {ref}`tutorials site<tutorials:sec_intro>`. There you can also find further
tutorial material to introduce you to key `tskit` concepts.

:::{important}
If you use `tskit` in your work, please remember to cite it appropriately: see the {ref}`citations<sec_citation>` page for details.
:::

:::{note}
This documentation is under active development and may be incomplete
in some areas. If you would like to help improve it, please open an issue or
pull request on [GitHub](https://github.com/tskit-dev/tskit).
:::