The Eastern Europe and Central Asia region has the world's fastestgrowingHIV epidemic. Although still concentrated, the epidemic hasdiversified, affecting several key populations in many countries. Thischange has increased the number of people in need, the ways theepidemic can spread, and the complexity of formulating an effectivestrategy to combat it. At the same time, international funding isinsufficient to cover the growing need, and domestic plans to coverthe funding gaps, in many cases, fall short. In this environment, the needto use data to make the best possible decisions about using availablefunds is essential.Tackling the World's Fastest-Growing HIV Epidemic tells the storyof how, in 11 countries across Eastern Europe and Central Asia, smallgroups of decision-makers and experts came together to carry outinnovative, groundbreaking analyses for each country. It details thesteps these nations have taken to strengthen their HIV programs basedon the findings while highlighting critical issues for the road ahead. Inso doing, the book also shows the potential of what can be done witha mathematical model and how it can support real-life improvementsin policy and more efficacious budget allocations. It is the record of aunique undertaking to improve public health investments that offerslessons for many communities.