The Open Logic Text is an open-source/ collaborative textbook of formal meta-logic and formal methods/ starting at an intermediate level (i.e./ after an introductory formal logic course). Though aimed at a non-mathematical audience (in particular/ students of philosophy and computer science)/ it is rigorous. The Open Logic Text is a collaborative project and is under active development. Coverage of some topics currently included may not yet be complete/ and many sections still require substantial revision. We plan to expand the text to cover more topics in the future. We also plan to add features to the text/ such as a glossary/ a list of further reading/ historical notes/ pictures/ better explanations/ sections explaining the relevance of results to philosophy/ computer science/ and mathematics/ and more problems and examples. If you find an error/ or have a suggestion/ please let the project team know. The project operates in the spirit of open source. Not only is the text freely available/ we provide the LaTeX source under the Creative Commons Attribution license/ which gives anyone the right to download/ use/ modify/ re-arrange/ convert/ and re-distribute our work/ as long as they give appropriate credit.