Sustainability is a key concept of fundamental importance in all aspects of ourlives and to society.Back in 2006, the 3rd International Conference on Hands-on Science held inBraga, Portugal, had as main theme ?Science Education and SustainableDevelopment?. The more than four hundred participants, that were comingfrom all over Europe and the World, presented at the conference a remarkablenumber of examples of good practices and discussed passionately this issue ina friendly and most productive way setting important and significantconclusions. The proceedings book of the conference remains a most valuabletool freely available to all at the website of the Hands-on Science Network(www.hsci.info).Almost two decades later no one (hopefully?) have doubts about theimportance of sustainability in all aspects of our society and to our future, andhow fundamental is the role of Science Education and a sound widespreadscientific literacy in promoting sustainability and sustainable development.From September 23 to 27 these issues are going to be further explored anddiscussed at the 21st International Conference on Hands-on Science in thecharming city of Pirenópolis in Goiás, Brazil. With an excellent organization bythe local organizing committee, conformed by members from all over theBrazilian state of Goiás, and the enthusiasm of all the participants teachers,educators, ecologists, researchers, world renowned scholars and local schools'students, an exciting and fruitful week waits us all.All presentations at the conference and the works selected, after carefulreviewing, to be included as chapters or abstracts in this book, will be avaluable tool available to all concerned and interested on these topics ofutmost actuality.