This book is available for free at http://openstaxcollege.org/textbooks/...
Biology is grounded in an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some topics have been condensed and combined; for example, phylogenetic trees are presented in the various ways they are currently being developed by scholars, so instructors can adapt their teaching to the approach that works best in their classroom. The book also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.
OpenStax College is a nonprofit organization committed to improving student access to quality learning materials. Their free textbooks are developed and peer-reviewed by educators to ensure they are readable, accurate, and meet the scope and sequence requirements of your course. Through their partnerships with companies and foundations committed to reducing costs for students, OpenStax College is working to improve access to higher education for all. OpenStax College is an initiative of Rice University and is made possible through the generous support of several philanthropic foundations.
Considering the fact that this reference in Biology is provided for free to all learners, it is pretty okay. Simple, straightforward, and offers many exercises and extra scripts that provoke further thought and research. It is not that aesthetically appealing, but this should not bother a student who wants to get the information clearly and quickly. I used this reference to study for an online biology class and it was actually much better than the reference that was mandatory in my prior college studies. You can find it among other free references provided by OpenStax here: https://openstax.org/subjects/science
Good text book. A free copy of this textbook can be viewed online or downloaded in various formats from openstax college. http://cnx.org/content/col11448/latest/