I am really impressed with this encyclopedia. I am learning about famous mathematicians I've never heard of before. It is brilliant that the encyclopedia covers maths of all different levels right from elementary GCSE level to degree level.  I will point out a misprint in this encyclopedia. On page 56 the the algebraic expression  (x + 1)(x + 2) / x(x + 1)  simplifies to  (x + 2) / x  or  1 + (2 / x)  and not as it says: (x + 2) / (x + 1).  Perhaps the publisher might like to make the necessary correction in the database stored on computer so that future copies of this publication show the correct simplification on page 56.  I have also noticed a misprint on page 70.  In an example of the chain rule for differentiation the derivative of the function:  (x^2 + 2)^100  is  200x.(x^2 + 2)^99  and not as it states: 200x.(x^2 + 1)^99.  This is probably a typing error since the digit 1  appears instead of 2.  Again, this error could be corrected in the database so that the answer to the derivative is correct in later editions of the encyclopedia.