I think you should contact them and understand the terms and conditions of the publishers if you are interested for publication of book. I heard from one of my friend who published his book through this publisher that once the book is published and given the copyright to them, the author need to buy even the hard copy for self from the publisher.
The publisher solicits for manuscripts from authors. While many experienced scholars frown at this style of publication, many young researchers have found their platform useful. Their papers are peer reviewed. They publish thesis and dissertations that have been certified by a committee of scholars.
Hi Adel Oueslati , do you mean Lambert Academic Publishing, see https://www.lap-publishing.com/site/home/10? Based on their website information they do have an international team of employees, I think. When a publisher works with peers, most of the time those content experts don't work fulltime for them, they are in academia or business and based on when they are needed they are consulted. I don't think Lambert Academic Publishing works that way. They just have employees in Mauritius, Moldova, Latvia and Mauritius.
But you can simply put that question forward to them whether their publications are peer reviewed. And if they say yes, you can ask who those peers are.