Have aliens really visited us? What do they look like? Where do they come from and why are they here? Have they given us messages in Crop Circles? What historical evidence is there that aliens have been involved in the evolution or creation of humans? Is there a UFO/Alien cover up? If so, how is it kept in place? This book embodies an attempt to give some answers to the questions above, based on a compilation and distillation of evidence collected during about 15 years of ongoing research. Although this book is not written for people who are new to these topics, "newbies" and seasoned researchers alike should find something useful herein. Detailed information and over 900 references aim to give the reader a perspective on alien intervention, alien abduction, alien contact, landings and crashes. The involvement of military and intelligence interests and their influence on the so-called "Disclosure" movement is also considered. Also included is a critical look at certain prominent UFO researchers, who seem to be helping to keep certain truths obscured or marginalised. The second part of the book studies various facets of the Crop Circle Phenomenon in a similar way to part one. Although most or all of the information in this book has been written about elsewhere, this work attempts a synthesis of reasoned analysis which, it is hoped, will enlighten the reader and give them a new understanding about why any official type of "Disclosure" is unlikely to happen, as powerful interests need to keep their crimes covered up.