This book provides a step-by-step introduction to graphical calculations related to angular momentum (matrix elements of irreducible tensor operators, sums of 3-j coefficients...) Chapters 1 to 4 are a nice alternative to the treatments found in the books by Elbaz or Brinks and Satchler. Chapters 5 to 8 cover the fundamentals of the Hartree-Fock method for many-electron atoms. Readers interested by the perturbative treatment of many-body effects in atoms can directly start from Chapter 9, which begins a series of chapters that forms a thorough approach to Lindgren's method for calculating energy levels in atoms.