The Contracts2.0 project aims to develop novel contract-based approaches to incentivise farmers for the increased provision of environmental public goods alongside private goods. The background to this work is the current imbalance in the provision of private and public goods from agricultural land management. This complex problem can best be addressed by using insights and methods from a range of disciplines. However, for methods and researchers to complement each other and contribute to the project aim, the parts must be brought together as a coherent whole. We developed a conceptual framework which draws on different concepts to explain the issues underlying the delivery of private and public environmental goods from agriculture. This document sets out the key concepts we use to investigate agri-environmental contracts in Contracts2.0. At the heart is our understanding of what a contract is, and which types of contracts will be studied. In Contracts2.0 we will focus on contracts that enhance the provision of environmental public goods and ecosystem services (Concept note 1) through supporting farmers or other land managers to adapt their land use and management. We distinguish three different contract types: 1) Payments for Ecosystem Services (PES) contracts including agri-environment climate measures (AECM), 2) Land tenure contracts, and 3) Contracts associated with the value-chain. Two further distinctions among all three contract types are that a) they can have a result-based or action-based contract design and b) they can have a collective or bilateral design. We draw on theories from New Institutional Economics to identify design features of contracts and contract governance. Contracts are inherently linked to costs and payments. We utilise the lens of payments for ecosystem services (Concept note 2) and transaction costs (Concept note 6) to capture these aspects of contractual arrangements. Institutional analysis (Concept note 5) offers a comprehensive fram