Biographical Dictionary of Christian Missions edited by Gerald H. Anderson is a five star enterprise. A whopping book of 845 pages including index and weighs in at more than 2 Kilograms. This book is an excellent reference tool for anybody interested in Christian missions and should sit in libraries of all Bible Colleges and seminaries and should be perused by Missiology lecturers and anybody interested in the Great Commissions (Matthew 28 and Mark 16:15), which should be all believers! "Go ye into all the world and preach the Gospel" - learn and be inspired by others.
Because it is a dictionary you will probably dip into the book as and when you are trying to find something on a particular missionary or mission statesman and hopefully they will be there. I have searched for some names who were missionary for some years, but not a lifetime and they have not been included, but to have a book of nearly all missionaries, just in the last two centuries would take a mighty series of volumes and people would still be left out.
After each personality, a description of their life is given often followed by a book or two or more where detailed information can be found. The appendixes of 80 pages in length is very helpful as it list missionaries by time period, then women, then martyrs, then by region of service (largely continents, but a number of areas are split again to narrow down the regions), concluding with biographies by selected major agencies, orders and religious traditions.