This document outlines the primary components and objectives of the Open Science Indicators Handbook. Objective and Scope: Deliverable D2.2 represents the inaugural release of the Open Science Indicators Handbook. This compilation encompasses definitive Open Science Indicators along with a preliminary framework for indicators on Academic, Economic, and Societal Impact and Reproducibility. Integration of deliverable D2.1: The content and methodology from Deliverable D2.1, titled A Data-Driven Methodology for Reproducibility Indicators, has been incorporated into a dedicated section of this handbook on reproducibility indicators. The rationale behind this integration is to provide a singular, consolidated resource that enhances the clarity and coherence of information. Accessibility and Continuous Improvement: To promote widespread accessibility and to foster ongoing refinement by the broader research community, the handbook will be hosted online on https://handbook.pathos-project.eu. It will be presented in a curated format, enabling sustained access and permitting iterative community-driven enhancements. The updated version is also avalible here Open Science Impact Indicator Handbook.